Asked to leave PhD program, is there any point in fighting to stay? My friend (who spent 3-4 years in a PhD program, discipline in social sciences) is encountering a serious situation with his committee/advisor. They are asking him to leave the program because the committee did not approve of the dissertation proposal. Earlier last summer, my friend had re-written the topic of the proposal.

Is this common? What can he do? He's a bit reticent to inform me but it seems he's not getting the support of his adviser. Can he talk to the graduate director to request to change advisors at this point? Or should he beg the committee to let him stay and try to somehow reach a compromise with his advisor on the type of dissertation he can produce. Or should he quietly leave and not put a fight? I suspect they might make things difficult for him if he persists to stay. Or should he talk to the graduate school?
When doing your PhD you need the support of someone, so it is no use trying to finish your PhD if everybody in your department is against you. So if there is a conflict between your friend and his advisor that escalated to such an extent that the two cannot fix it themselves, than it is time to move up in the hierarchy. The graduate director can either try to mediate between your friend and his advisor, or try to find an another advisor. 

If that fails, then that is a horrible situation for your friend, which in most (but not all) cases a professionally run department should be able to prevent. In that case there is pretty much no other option but to leave and try his luck at another department. However, beware that that department will in all likelihood be in the same field, and scientific fields are like small villages: they gossip a lot. So, your friend will most probably enter that new department with a "reputation". Also your friend should consider his own role in the conflict in order to prevent making the same mistakes again. Remember, he already has a reputation, so he probably won't be treated as leniently as a new PhD student.