I actually think it is a good idea to help them once they are on the right track. It is pretty easy to tell if they are...the druggy friends are gone. Drug users don't like to hang with those who don't indulge with them both because misery loves company and because that's what they do to socialize. They also suddenly seem to understand that they have no choice but to conform if they want to get off the streets an d stop depending on their often very two-faced drug buddies. Working is a big GOOD JOB!!!! It may not mean the drugs are over, but it is a step in t he right direction. I would be more of an emotional cheerleader than a financial one, but that's up to the parents.
I do think the older they get, the less apt the parents are to believe there is any real change and I think stopping young is more promising that continuing the behavior into the 30s.