I think you hit the nail on the head when you say the home life he has could be affecting him and making him anxious. Yelling and misbehavior at home does affect children, it will stay with him all his life unless it is addressed. Your best bet when he is with you, is not to feed into his behavior, make no issue of it, its okay for him to have a light on at night many children are concerned about the dark.It would be a good idea to talk to his Mom and see if she has some ideas to help him,its also good he has you in his life we all need some caring....