I think the issue with C is resolved for now. N said that C approached him yesterday and indicated that N had indeed been correct, that anorexia is a "mental disorder." C had gone home and talked to his mom -- who either looked it up or clarified her original statements to C. Anyway, I could tell that it wasn't bothering N anymore because I had to ask him about it.
N is going camping tonight. I'm not nervous about it in the same ways I've been in the past. He'll eat fine while he is gone (or he knows that he won't get to go camping in the future). I'll also make sure that he eats well before and after. I hope he has fun and is able to feel confident with his friends.