Sounds like this guy might be autistic, maybe even a schizophrenia or something like that. It does sound like he's menatally impaired in some way though. How old is he? If he's autistic or "mentally retarded" there's not too much you can do about it. I know, beause I'm a mom to a special needs little guy who is severly handicapped. Maybe just try ignoring him, which I know can be hard, but I don't think being mean to him or hurting him will do any good. Maybe speak to the principle and the principle will get in touch with this guys parents. I wish you luck. You seem like a nice guy and you seem to have compassion for this fellow, which is real good!