So Far, So Good
Seems to me like given the circumstances, things are already looking up and pretty great.
I wouldn't recommend asking him to treat you like a father, because you just aren't his father. You do, however, deserve that he treats you with respect just like he should treat other people with respect, and just like he should treat authoritarian figures and people on his side with respect. That last bit is important. You are on his side, and he knows it. It can be tricky to ask of him though, as he's been dumped before by people who were supposed to care for him, so he may try to push to see if you'll do the same and see it as a natural thing. Just show you won't give up on him, but that you won't be a doormat and actions have consequences.
I would also attempt to set slightly stricter rules on some key points and discuss them with him.
Specific Points of Concern
Out Late - Cause for Concern
11pm on a school night is a bit late, yes, I'd say lights should be off by 10 or 11pm (most of the time). It's not just as a way of controlling his whereabouts and by fear of him wandering in dark alleys or whatnot, but I'm more concerned about that setting a pattern that will hinder his learning and prevent him from getting a familiar and regular routine.
- What is he doing out at that time?
- What time does he have to get up for school in the morning?
So, I'm not too fussed about it, but I'm a bit concerned if that happens way too regularly and if the whereabouts and actions are unknown. Of course you have to establish trust and not spy on him or anything, but at 16 I'd expect him to be home earlier than this. I don't know it is where you live, but where I do at 16 I had homework to do, and my after-school routine was:
- getting home
- eating a scary amount of food (my father was shocked to see my brother and I actually cooking meals for ourselves at that age because we were hungrey all the time. Normal teenager biorythm, best to stash lots of food!)
- slacking, walking the dog, playing with friends outside, and (later) video games or other things delaying 4.
- after dinner:
- movie on 1 or 2 days a week tops if homework is done,
- or homework if it isn't done
At that age I'd occasionally go out with my parents, or on more rare occasions with friends in groups (e.g. for a concerts), but most of the time during the week I'd be home by 8pm (dinner time), except on football training nights.
Then I may stay up late at home, but generally that was only for the occasional movie night or because I was late on my homework or preparing exams (I wasn't the smartest student, nor was I the most studious, and I was kind of slacking off before dinner).
Though, of course, back then some things were less ubiquitous: cell-phones, internet, video games... they were there, but not as much of an integral part of your life. And when they appeared, they took more and more importance on my schedule, so I guess that's another problem if he's home anyways... but that seems better than being out.
Hey, I guess he's not out alone and you can tell yourself he's quite social. Not a bad thing in itself.
Skipping Dinners - Not OK
Seldom home for dinner isn't OK.
- What does he eat when he's not home?
- How does he afford it?
- Why isn't he home? Does he give a reason? Is it because of the dinner itself (food, atmosphere, memories ...)?
Dinners are family time. You aren't his parents, and you aren't really his family, but your his "circle". Dinner is the time to catch up, share what's on your mind, and check up on things.
It's also a good time to bond, whether you want it or not, and a good time to stimulate other development aspects. Just don't turn it into this.
Phone Stuff - Seems Fine
The phone-related seems pretty standard and acceptable to me. And good on you for giving him the phone. I had a very good relationship with my parents and they forced me (I have to have been the only kid who had to be forced to be GIVEN a cellphone...) to carry a cellphone when I took up to drive a motorbike. But every time they'd ask me to call when I'd arrive to a destination or something, I'd invariably forget. I don't think that was a lack of respect, just a matter of it being really easy to forget. As long as he writes back AND also picks up when you call, that's fine. What matters is that you can now he's safe and can trust him to call you if he needs it.
Skipping Classes - Not OK
Skipping classes isn't OK, even one per day, even one per week, even one per month. There's no reason for that, apart from being sick or helping someone else out. I wasn't really top of the class but I never skipped class except for serious medical problems or when I covered for a buddy, and that'd also be a possibly stupid reason. Your conditions are that you give him shelter and try to get him to graduate, so it's up to him to take that seriously.
Plus, skipping classes might have unintended consequences.
- Why is he leaving in the middle of the class? Boredom? Restlessness? Peer-pressure? You need to find that out.
- Have you verified with teachers that he actually does leave in the middle of classes and that you have the whole story? I suppose you did, but just in case...
- Have you talked with both him and his teachers about this? What's their take on it, and what consequences will that have? Is he clear on this? In my area, skipping classes would be quickly cause for a temporary exclusion, and then possibly for a more permanent radiation and obligation to be sent to another school, and that's when the real fun would begin...
From a personal experience, skipping classes is most of the time a peer-pressure related thing. Others do it, and it's a matter of social status and of the crowd you want to associate with. That's the tricky part of address, as if that's the case he obviously believes he belongs (and WANTS to belong) to these groups. And it's not necessarily groups of "bad-seeds" (many good and relatively quiet students skip classes as well), but the repercussions are not the same for everybody.
When I was a teenager, my parents had a strange rule on that: we don't mind if you skip classes, but we'll mind if we know about it. When I tell that story, most people interpret it as them not caring and not setting rules and giving us a free pass, but the way it was meant was more that they trusted us to be in class, trusted us to have the judgment to skip bullshit classes if we felt it was necessary (because they remembered that not all classes were valuable), but that it shouldn't be done at the expense of another thing: respecting authority. Theirs, and the school system. That it may be broken is one thing, but you won't fix it by being out of it. And, well, also that if you are going to do something, you should do it well - even slacking and not getting caught. However I never thought this was bad advice, and I didn't slack classes and neither did my brother. It was also a way of teaching a sense of responsibility indirectly: deal with YOUR problems, and don't make it OUR problem.
Does he do any? If not, I'd strongly recommend it takes up some. Which one doesn't matter as much, but if possible something that promotes some social values. Running and athletism will be good to teach you perseverance and other things, but not so much necessarily in lieu of respecting others. A martial art or a team sports will do better at that. On the other hand, relationships are a worry in team sports if his social interactions tend to lead to bad habits (as you mentioned drug use, possible violence and police). So, look up first how the social element plays out in your local sports clubs.
But in general, I'd say even the worst possible sport you could pick, even with bad instructors and bad teammates, would be a good thing for him. It'd keep him healthy, add more structure to his life, and fill up his schedule so you know where he is and he's not tempted to be anywhere else.
Surely there must be some sports he's interested in. It's an investment, both financially and time-wise, but it's a good one.
Other Extra-Curricular Activities
Anything he likes to do? Writing, reading, watching movies, playing video games, etc...?
Anything that's a positive force in his life is a leverage for you, both because you can have an impact on them as punishment if he strays, but also (and mostly!) because you can use that to push him forward.
More "Family" Time
Again, you're not his family, but what matters is to develop a mutual bond built on trust, respect, and - hopefully - friendship.
Have you gone on vacations together? Done week-end outings? Gone to see a ball-game, concert, festival?
Psst, Actually "Family Time" is a Head Fake
I have many memories of my childhood when my parents dragged me to things I wasn't particularly interested in. And nowadays, even the things I found annoying at the time are things I'm thankful for, because it gave me perspective on things, and filled my brain with tidbits of information that I found useful later.
Sometimes, "Family Time" is just an educational tool.
Build His Self-Worth and Confidence
From what you describe, I'd bet that kid would have reasons to have a low self-esteem. Maybe he doesn't show and he's a rugged, maybe he looks confident, but having been displaced from home by his own caretakers (I'm not sure I even want to call them parents at this stage anymore) he probably doesn't feel too good about himself.
Following the point above, make sure to value the things he does right. A bit like the One Minute Manager teaches you: catch people doing something right, not just doing something wrong!
Also, try to not show that having him is just a social responsibility, a burden or a duty. Get him involved in what you do.
Get Him a Job
Even a small one. Even a summer job, a part-time thing, or a stupid job at your employer's. Even find him a neighbor's kid to baby-sit occasionally. Even a make-believe job, like asking a friend or neighbor to ask him if he can help with a problem with a computer problem. Surely an old lady somewhere doesn't have a Facebook account and would agree to pretend needing one, or learning to use Word, etc... (Sorry for the stereotypes and the lack of better scenarios, but you get the idea.)
Anything that gives him responsibilities will be good and relates to the previous point on building his self-worth. It teaches a lot of other things, obviously, but for him I think that's the main point. And again, it will also, as mentioned for other things above, fill his schedule and keep him - by lack of a better expression - "in line".
Keep in Touch with his "Real" Family
Make sure he knows you are trying to keep in touch with them, and for the right reasons. He may not seem to want you to, but he'll probably value that you do, if he doesn't get the feeling that it's to get rid of him (I can't stress that one enough: he's been jerked around and dumped, a pretty strong inner fear for him is probably for that to happen again).
But, generally speaking, looks to me like you're doing alright and keeping at what you're already doing seems great. Congrats on an honorable and valuable show of kindness.