It sounds like your friend needs to see a psychiatrist. Unfortunately, it also sounds like she's too defensive to accept m(any) outside beliefs. If you could find a preacher who isn't extremist, and have him/her talk to her, it may help. I'm guessing this because she may not accept what a fellow christian of her rank says.

But I agree with RCLefty. Use her weapons against her. That's all I can say. I've never dealt with exremists like that before, so I can't help out much. Good luck, though.