[Alan Anderson]

I think both problems call for similar action to begin with.

Quietly find out whether other students truly feel about the "problem mentor" the way you do. Ask them if they would support your position if asked about it by an adult, and let them know you intend to approach the mentor and tell him that his behavior is causing problems. If you can be confident that your teammates won't leave you looking like a solitary rogue, go ahead and tell the mentor of your concerns. Don't let it turn into an offense/defense situation; just make your point known and don't get drawn into a shouting match.

Quietly find out whether other mentors truly feel about the "problem student" the way you do. Ask them if they would support your position if asked about it by a student, and let them know you intend to approach the student and tell him that his behavior is causing problems. If you can be confident that your teammates won't leave you looking like a solitary rogue, go ahead and tell the student of your concerns. Don't let it turn into an offense/defense situation; just make your point known and don't get drawn into a shouting match.

Now everyone will have the same context, and you can try to work things out from there. Hopefully the person can change his problematic behavior once he has it pointed out calmly. But if the person doesn't agree that he is a problem, while others around him do, then you might have to be prepared to ask that person to leave for the good of the team.