Well if the lease is on your and your friends name then he can't say tell you to move out. And he should grown an extra pair of balls to sublease the apartment to someone else without your consent (written). But you can tell her to get out of the apartment or share the utilities/grocery/and other bills except for the room. In that case you can file the case at small claims court.  Divide the costs of living by the 3 (except for the room) and take his ass to court.