You can't cure her. You are not responsible for her mood shifts. You are only responsible for you and YOUR well being just like she is for her own.
I'm sure she makes you mad but you don't threaten to kill yourself. She is using it to manipulate you. Please don't play into her game. Take care of you and get out of there ASAP. So sorry you are having to live with this. I know how terrible it hurts to be blamed and think it's all your fault.