M.S.
If your son is worried about his allergies to peanuts/eggs, then that's a good thing. He's aware of what he can and can't have. It's a good building block. Another good building block is "stranger danger". I had my youngest watch the Safe Side video by John Walsh and the creators of the Baby Einstein videos. She loved it, and it was very educational. You could build from that basic structure of how people you don't know are "strangers" and so on.....the same rule applies to "taking" things from people you don't know well. Even if it's a kid, sometimes kids take grown-up things without even knowing it's not safe. That's a very slippery slope...the whole kids and safety. Good luck!