Hi Justine:
First off let me say how sorry I am that you have to go through this. I know how difficult it is and how it can consume your thoughts.
I, too had a sibling (my only one) who had an addiction. He was addicted to all kinds of drugs for 14 years. It was hell on the whole family. I was always afraid for him, always mad at him, always annoyed with him. He would disappear for months until he had a dry spell, then he would stop by. I could never contact him because he never had a phone and was constantly moving.
The one thing I wish I had done was have an intervention with anyone and everyone who loved him. I didn't and we lost 14 whole years together.
The sad, true fact is, though, that NOBODY can make your sister stop until she decides she is ready. Forcible rehab doesn't work because as soon as she gets out she will be doing exactly what she was doing before. Maybe worse because she needs what she wasn't getting very badly.
I implore you to NEVER GIVE UP ON YOUR SISTER. She has a disease that she has no control over. For people like us, who don't have addictions, we really can't understand why they can't just stop. If it were that easy, I'm sure they would.
She may, eventually, clean herself up. All you can do is wait. And talk to her when she calls. Smile when she visits. And continue to love her. Don't harp on her about her problems. Maybe she is trying to escape her world when she contacts her family. Maybe she just needs someone who really knows who she used to be and she just might need a loving heart to talk to.
My brother cleaned himself up after those 14 years. He was clean for 4 years before he took his own life. I have so many regrets, so much sadness. I do believe that people with addictions are fighting their own 'demons'. I believe they are very gentle souls who have been hurt so badly that they don't know how to deal with a life without covering their pain.
Don't ever forget the little girl she used to be before life got ahold of her. You know who she really is and who she really is, without the addictions, will never change.
I wish your sister a speedy recovery and I wish all the best for you.