Yes, I would forget trying to make of this person a "friend," and help him as you can, being far less available to him than you have made yourself. Otherwise, he can become a problem -- your problem. No, it's not about his sense of humor at all. It's about two people who don't mesh. Decide how much you want to be in his life -- you are a good helper to this young man -- and hope you can handle it firmly enough to make him back waaay off. If you can't -- well, sorry. You have to decide between him and yourself at that point.