As an ex-lecturer in a university, I am really surprised that your friend does not seem to be committed to her students. When did the semester start and when does it end? I wonder when did she know about when she was going to get married? It is normal practice in educational establishments that teaching staff terminate their employment at the end of a semester.
Your friend needs to see what the employment contract says and act according to that. As we are not privy to what her appointment letter says, it is difficult to advise her how to terminate her job immediately.