I know LB is a thoughtful little guy, and my guess is that he is, in his own time, trying to sort out the changes in your house. I don't think you need to worry too much because the fact that he ASKED you is awesome. Does he spend time with you in your room at all? When you say he can call you, do you mean on the phone? It'd be a cool idea maybe if he thought he had a special Mommy-hotline, heh. Knowing he has you when and if he needs you is probably mostly what he's concerned about, as well as making sure he's not going to lose anyone else important in his family due to the shuffle.
I think you're an awesome parent, and he's a lucky kiddo. *hugs*