It’s a difficult one.
Me and wife have a close friend whose functioning coke addict (she would deny this but doing lines in your own home on a week day night says otherwise to me).
She’s depressed because life hasn’t turned out as well for her as it has for some of us but never connects the two even when you spell it out to her.
Just after New Year she hit what we thought was bottom, cried for help, we got her family involved (she’d hidden it from them; they just though Lady Luck didn’t shine on her..?..) and for about two weeks it looked like she was making an effort then we went out with her one evening and she had ‘just a couple of cheeky lines’.
Unfortunately like TJ says he won’t stop until he does, addicts are addicts and rehab only works for those who are ready.
As hard as it is we’ve had to step away and let her get on with it; my personal feeling is as long as addicts know there are people to fall back on who will pick up the pieces they never have the impetus to change.