I need to help her see the point...?

I will be blunt, your friend is a medical case, only a psychologist can help her not you. For your own benefit, you must be clear headed and just be around to support her but don't get actively involved in her life because it might cause harm than good for both of you. Just lend her that shoulder if she needs it and try to direct her to professional help. That's the best a friend can do.