How to manage unruly student who is ruining team

[DonRotolo]

Originally Posted by BulldozerChick

I can't do this alone.

No, you cannot. And should not.

Enlist help: School, teacher, parent(s).
If the member does not attend your school, or you are not a school team, still ask a counselor (at your school) for ideas and help, at least in getting help.

This is beyond even what a large majority of mentors can handle (never mind students): It requires professional training and considerable insight.

I wish you good luck and perseverance.