OP, no matter how you try; you cannot “fix” your friends. And unless the advice is asked for, they rarely take advice. If you were right, your friend will eventually discover for themselves that you were right and then may be open to advice… It rarely works out well to tell your friends or family that their BF or GF or mate is bad for them and it often makes them feel like they have to choose between them and you. I understand that sometimes it’s hard to keep silent unless asked and in extreme cases you may have to speak up. But often the consequences are exactly as you are seeing.

Sad as it is, you can't help someone who isn't ready to be helped. I can only hope your friend will remember you when she realizes she needs to get out.

Or maybe you're the creepy, controlling "friend?" I'll bet you tell people you're a "nice guy." She seems to have a type.

Sounds like they deserve each other.