One of the many tough truths in life is that we cannot "fix" other people. If a person is going to find recovery (from anything), it's truly a matter of the heart. It's a matter of complete surrender to God. It's a matter of wanting to get better, and wanting it more than anything in the world. It's the gift of desperation.
You may be familiar with the term, "rock bottom." That's what it took for me. I had to get there on my own. Rock bottom is not always just circumstantial - in fact, it rarely is. Rock bottom, in my experience, was circumstantial, emotional, and spiritual. I was spiritually bankrupt. It was a darkness that can only be compared to being locked in a closet with no walls, no door, and no God. My soul had to cry for help.
When that happens, recovery is sure to follow. You might be thinking, "ok, but my situation is a little different...", and it probably is. But it isn't to God. God will help anyone who asks Him.
Just don't give up. Always keep praying for the ones you love. And accept the hard truths. You'll find that life gets better when we let God do the work.