Kid has a problem..I have no clue what he has though.?

There is this kid in our Music cl, he gets really high marks like in the high 90's. But the thing is, the cl is bothered by his behavior. He talks to himself and makes jokes he only laughs at. At one point during a practice one person told him to play in a lower octave and he started to freak out like mad crazy for literally no apparent reason. I've tried talking with him but it's really difficult because he does not cooperate properly. How does this guy get high 90's if he can't communicate properly with other people in the cl?