Thanks for using Just Answer.
I've worked in the field of Substance Abuse for over 20 years and can give you a few pointers.
The first thing you need to do, for you, is find an Al-anon meeting and go. Don't be concerned that Al-anon is for alcoholisc families - addiction is addiction and those meeting are the best. Don't make any excuses, don't wait more than a few days to get to a meeting, go, no matter what. It will be the single most important thing you do - I promise. You will learn more there than in any other place.
The second thing you have to do is let him start taking full responsibility for himself (they will tach you HOW to do this in Al-anon), but the basic idea is that every tiny thing you do for him is one less lesson he needs to learns for himself. He WILL NEVER GET BETTER if you continue to monitor and "help" him in any way. You can't control his meds, you can't give him money, food, transportation - NOTHING (maybe rides to meetings).
He should be attending AA (alcoholics anon) meetings, not NA (narcotics anon). AA is THE largest group in the world (not jsut for recovery) and they know what they are doing - they have been doing it right for 100 years. Bargain with him - if he wants food he has to attend a meeting for each meal. Don't back down no matter what.
Buy the AA "Big Book" it will tell you everything you need to know about addiction, recover and addicts.
Lastly, consider having him attend a LONG term (LT) treatment facility. Long term residential treatment is where the addict lives at the facility for a minimum of 18 months, they do individual therapy, group therapy and teach the residents all new living and vocational skills, so when they get out - they have skills on which to support themself.
The only guarantee here is that if YOU go to Al-anon, you will learn all the details you need to be the best parents you can be for him.
I hope this helps... please feel free to email back with any questions.