It sounds like what you're living with your friend is incredibly painful and baffling. Creating some distance from your friend, for now, as heartbreaking as it may be, sounds like a wise and self-protective move. Sometimes we need to feel our compassion for others from a safe distance, and, focus more on compassion for ourselves. Perhaps, if it's possible, you can also remain open to a time in the future when things might be different and when, maybe, she will be able to own more of her own behavior. So too, I find it helpful to ask myself, what in all this can i use as a teacher? Is there a way that I can grow and evolve through and from this difficult process. Every situation is our teacher and viewed that way, even something awful like this can be welcomed with curiosity.