For N (now 30), prison and mandated rehab was the turnaround. He served 6 months in prison and then had an additional 3 months in a facility with addiction services and counseling, job training and work release (still part of the prison system). When he first went to prison - not his first time arrested and jailed but the first time he was actually convicted and sentenced to more than time served - he was bitter, angry, entitled. You better take my calls. You have to come down here and bring me socks and underwear because prison doesn't provide them. Call my lawyer for me. Do X, Y, and Z for me. Angry abusive language if I didn't comply. And a lot of "This is BS/I don't deserve this" attitude. I had to go no contact for a while, letters only, and then gradually started visiting. He got much more humble over time. By the time he was in the rehab center, he was very humble and respectful. He was very appreciative of visits and anything else I did for him, without seeming to feel entitled. They had an outdoor courtyard with picnic tables where families could spend time together on nice days. I brought him homemade meals a couple of times and shared picnics with him. He talked to me openly, and cried with me. He apologized and took responsibility for where he was in life. We talked together about his hopes and dreams for after he got out and what he could do to make that happen.
He's had some slip-ups since then, but the change in attitude has been permanent. He doesn't blame anybody but himself for his mistakes, and doesn't expect anyone else to bail him out (literally or figuratively). He has a family now and is committed to being a good dad to his son and stepson. He is finishing an apprenticeship program and holding down a job that requires him to be up and out of the house by 5:30. (This was the kid I fought with all through high school because he would never get up on time.) Even though he's almost 2,000 miles away now, our relationship is closer and better than ever.
With C (almost 33) and S (28), it's been a different story. Neither is sober yet, and neither is taking responsibility for themselves. I've had to put firm boundaries in place. They've both raged against those boundaries - and sometimes still do, when they are desperate - but as they have gotten older they seem to understand more and give me more respect, even when I'm telling them no. I guess we've reached a place where I don't try to change them, and they realize I'm not responsible for fixing their messes. They still have their rages, but it is rarely directed at me anymore. So even though they are still using, my relationships with them have improved. I can only hope that this means they are taking baby steps towards taking responsibility for their lives and maybe, eventually, recovery. But if not, at least we have found some moments of grace in the storm.