helpless girls & broken dolls

I have not seen my sister in a long time until the beginning of May.
Initially she appeared alright, sometimes a little fuzzy with zig-zaging conversations. She'd been zoning out often and returning to the conversation on a new subject.
She didn't answer questions directly but said what she wanted to.The question she evaded never really appeared to have registered in her, like selective thinking.
Initially, she was very active. More and more, as the month progressed she's become passive (far from her natural state)
She'd been talking about morphine patches, Duragesic and Norco and I knew that she'd come across some people she can obtain them from.
Driving around with her as teenagers was tough. En route she'd have the window rolled down waving & shouting to her drug providing friends. Not wanting her on so much drugs and I'd speed by these "friends" foolishly thinking I could take her away from drugs.
I introduced her to a different circle of people, but she had no interest.
Years have gone by. So many, since she'd begun resorting to drugs on a daily basis in high school.
Spending days going into nights convincing her to detox and spending hours phoning rehabs begging for a spare bed. Once after an exhausting day/night of phoning, I warned the nurse that she may very well die and very soon, if she could not locate a spare bed. Fortunately the nurse was moved and arranged to accept her in the facility. N was pretty much unconscious by this time and never protested the long ride to the hospital.
I was as strong willed as she was.
The guy she'd lived with for many years was shot dead in the ghetto section while looking to score for her.
We are both adults now and N is obviously using chemicals heavily.
She had a "stomach ache" (yeah, right!) yesterday morning when she visited me so she spent literally the entire day sleeping in her bf's truck.
When he got bored after a few hours of her sleep, he disappeared and turned up that evening drunk. Since neither was capable of driving, they spent the night sleeping in the vehicle. So much for the "visit".
She DOES what she wants. I no longer try stopping her. My only hope is that she uses some caution and doesn't get hurt or worse.
Her voice is a very weak, slow attempt at staying awake during conversation. Sometimes she's asleep before she has finished a sentence, most often it's just a couple words before she's back to sleep.
For someone involved , but not involved heavily into drugs, we feel mostly helpless.
This isn't a child, though it can seem that way.
N. once upon a time was a very pretty, bright and popular girl. I'd never dreamed then that she'd need drugs at all.
I was more the misfit, the weaker and obviously weird one. If either of us was to make drugs a way of life, I'd have thought back then, it would be me.
I don't feel like the winner, I feel like I'm losing my sister and that's a feeling I've suffered for so many years.
Accepting defeat has been a long term process.