There are a lot of things going on that may or may not be related. However, many of the symptoms you describe are familiar to me -- my son behaves in the same way very frequently. In our case, he has attention deficit hyperactivity disorder (ADHD).
I want to be clear that I'm not a medical professional, and you've only provided a snapshot of your nephew's life. Don't consider my advice a diagnosis, because it could be wrong or there could be other problems... but it may give you a starting point to work with.
The US National Institute of Mental Health describes the symptoms of ADHD on its website. (I'm including below only the ones that are strongly related to behaviors that you mentioned.)
Children who have symptoms of inattention may:
- Be easily distracted, miss details, forget things, and frequently switch from one activity to another
- Become bored with a task after only a few minutes, unless they are doing something enjoyable
- Have trouble completing or turning in homework assignments, often losing things (e.g., pencils, toys, assignments) needed to complete
tasks or activities
Children who have symptoms of hyperactivity may:
- Have trouble sitting still during dinner, school, and story time
Children who have symptoms of impulsivity may:
- Blurt out inappropriate comments, show their emotions without restraint, and act without regard for consequences
And while lying about whether he has homework may sound like it's not on the list, I'd wager that he simply finds it easier to make up stories than to do the assignment.
Essentially, he finds it very difficult to pay attention and control his behavior. This can be just as frustrating for a child to deal with -- because he would like to behave but gets so easily distracted that he can't remember to behave -- as it is for parents and teachers who are continually reminding, punishing, and redirecting!
The NIMH also includes Tips to Help Kids Stay Organized and Follow Directions.
Schedule. Keep the same routine every day, from wake-up time to bedtime. Include time for homework, outdoor play, and indoor
activities. Keep the schedule on the refrigerator or on a bulletin
board in the kitchen. Write changes on the schedule as far in advance
Organize everyday items. Have a place for everything, and keep everything in its place. This includes clothing, backpacks, and toys.
Use homework and notebook organizers. Use organizers for school material and supplies. Stress to your child the importance of writing
down assignments and bringing home the necessary books.
Be clear and consistent. Children with ADHD need consistent rules they can understand and follow.
Give praise or rewards when rules are followed. Children with ADHD often receive and expect criticism. Look for good behavior, and praise
These are strategies which could be useful whether or not your nephew has ADHD or a similar attention problem. Organization, structure, and clear rules are helpful ideas.
Specific to the homework problem, I suggest asking the teacher to send home a note if there is no assignment -- that way your nephew has to show what he brought home every day and it is either homework (which he then must do) or a signed note saying he has none (in which case he's free to play). Without a way to check that he's lying, he'll continue to do it. He gets to play instead of doing a dull assignment, and he isn't thinking about the consequences of not turning in the homework, or of failing school, or anything else -- just about playing!