Good Job! You will probably find if you step away she will either help herself, or someone else will. Once everyone stops "helping" she will have a better chance at getting better.
With an SLH she will be in a home with others who are working on sobriety. No drugs or alcohol are allowed in the home and they usually require random testing. There are rules and a community environment where they hold one another accountable. She will most likely be required to get a job immediately, or help pay her way by working within the home until she can do so. Often there is a deposit that will not be refunded if she is kicked out.
I'm a sister too but not so desperate these days because I learned I am not in control. I rarely feel all those bad feelings I once felt when thinking about my brother and he's doing better without my help than he was when I thought I could do something to heal him. I even had my screen name changed and took the word sister out of it.
Hugs and Prayers for you and your family.