((Sisofanaddict)) - welcome to SR, though I am sorry for what has brought you here.
I think you've gotten excellent advice above and totally agree with it. BTW, I'm a recovering crack addict, myself. Not only that, I'm a recovering codie (codependent) and have spent decades being held hostage by addicts/alcoholics before I realized that it was only because I allowed it.
I know it's scary when they threaten suicide "if you don't......" of if you DO "......." However, we A's (addicts) are extremely manipulative, for the most part. We will do and tell you whatever we can in order to keep getting our dope and/or money for dope. We don't set out to hurt those we love...we're simply doing whatever it takes to get high. When/if we choose recovery, we will be just as headstrong.
The only thing my loved ones did, that helped me when I was actively using was to detach and stay away. The essentially told me "we love you, but we don't want you anywhere near us when you are like this". No money, no roof over my head, none of that. They went on with their lives.
When I got into recovery, I was so thrilled to be able to get back into their lives, and was welcomed back, though I did have to prove I was trustworthy again. I understood..that's part of my consequences.
I left my XABF behind as he was still using crack. It's hard...so very, very hard. I've had to detach from a few friends/coworkers for the same reason. Living on either side of addiction is hard, but I hope you continue to read adn post here, and that you let your sister focus on HER while you focus on YOU. It truly is the best thing for boh of you.
Hugs and prayers!
Amy