She is making choices and clearly doesn't want help. You will tear yourself apart trying to help her only to have it thrown back in your face each time. As sad as it may be, you have to think of your own wellbeing and mental health above her. You have tried, which doesn't mean you can't try again in the future when her circumstances change or she realises she needs and wants help.
I don't think it's wrong if you don't want to have anything to do with her. Maybe you're now just tired and fed up of all the wrong things she has done to you in the past. However, since she's still a family of yours, I think you should find a way to help and support her, maybe give her a little advice about life and recovery.