What should i do in this situation, i feel so guilty?

The situation is pretty bad because of your friend like you say I'm sure he won't want to be treated as a charity case but the matter of fact is that people who normally go through these situation in their lives just are waiting for someone to care what they are going through. They want someone to be their honest friend. They want to be loved. And most of all receive what they don't receive at home..Love, understanding and a good friend to talk to from time to time. Maybe they are days that he doesn't eat but you could take a certain day of the week and invite him to a good lunch. Maybe not all the time but sometimes and don't make him feel bad..Say hi..good morning..good afternoon or whatever don't make him feel less then others cause he will resent you and think that you are like the other teenagers in school. People like him could be a little strange but you can get to know him a little better show him how to be when everyone is around get to show him how to socialize with others..( Of course you could do this when you two are alone this way he doesn't feel out ) Start with a couple of friends or one by one. Anyway I hope I help and good luck.