I'm 25 and I babysit my cousin occasionally. I like puzzles (a good deal) and I have since I was a child. My cousin is old enough (6) to know this too.
My older brother sometimes looks after my cousin and will sometimes be stumped by the puzzles my cousin will present him (more like riddles, I guess, like "What gets wetter as it dries" kind of stuff), so my cousin often presents him with new puzzles every week. My brother doesn't seem to mind too much since he can answer most of them. My younger sister is not a fan of puzzles at all (she says they're too conniving, which I can't disagree with) so if he presents her with a puzzle, she actively does not solve it and encourages him to tell her the answer instead of solving it herself.
On the other hand, I've been doing mental gymnastics since I was a kid, and if he hands me any puzzle, I immediately know the answer (he's getting his puzzles from books I used to own). When he was younger, I would only solve the "hardest" puzzles, i.e. if he came at me with a puzzle rated with four stars our of five, I would solve that one, and if he came with one with one or two stars, I would encourage him to tell me the answer. That's how my dad got me into puzzles when I was young.
I do not ever solve puzzles without walking him through the steps (unless he tells me the answer first and the answer is correct). It worked for a while, but he caught on to the ratings really quickly and now he only brings high rated ones.
But I can't get him to do the puzzles himself (or sometimes I can't get him to work on an easier one that would help him learn to solve the hard one). For example, he came to me with a 5 star puzzle that I could water down to a 2.5 star puzzle. I changed the puzzle to be as follows:
Sophie: "Someone ate my cookies! I wanted that for later! Who was it?"
Person A: It wasn't me!
Person B: It wasn't A or D, I saw!
Person C: But I didn't eat it either!
Person D: Person C is telling the truth.
Only one person is lying. Who ate the cookies?
The problem I watered it down from had about ten people (and altogether is really long so there's no point in posting it). This puzzle is something he can absolutely solve on his own, but he won't do it. Instead he complains that I'm not being fun or I'm not helping him. If I solve the puzzle he gets annoyed that I'm not helping him and if I walk him through the steps he complains that I'm not letting him think. If I ask him "What do you think we should do first/next/now?" He says, "You already know the answer, so it doesn't matter."
For the above puzzle, he knows (and has stated) that the key to solving it is that only one person is lying. But if I ask him, "Which person is telling the truth?" He says, "You already know so it doesn't matter." But he doesn't seem to be saying it in a happy way, like it's a joke? He seems upset. He'll happily solve puzzles with my siblings or my parents, even though my dad is more of a puzzle beast than I am.
I really do love my cousin and I'm glad he likes puzzles too, but I can't get him to solve them on his own if I'm around. I think it's because I know most of the puzzles in his books, but even buying him a book that I didn't once own hasn't changed this behavior. I don't want to stop solving puzzles with him, but he seems to just get more and more stubborn about not solving them with me. Is there something I can do to make him feel more comfortable solving puzzles with me? Or should I stop solving puzzles with him altogether?
(I put the answer to the puzzle in a spoiler tag if you're interested in it.)
Only one person is lying. If A is lying, then B is also lying. If D is lying, then C is lying and if C is lying, then D is lying. And if B is lying, there is more than one cookie eater. That means the liar must be Sophie.