I always like the one "Lord, put your arm around my shoulder and your hand over my mouth."
One of the best lessons I learned was to mind my own business. I learned that if something didn't have my name written all over it...I didn't own it. And I learned that what anyone else thought of me was none of my business.
Each word of that will sound crazy to the newcomer, but in time each one will make so much sense you'll come to live by those words.
Dixie, it sounds like your son will be living with his wife, yes? My thoughts are to treat him like any mother would treat a son, with respect for his privacy (which means not questioning his recovery or his relationship each time you talk to him), with love and care, and not feeling like you have to walk on eggshells for fear of him getting upset and going out to use.
Just be yourself, work on your recovery and let him work on his, and try to find some happiness in every day.
Hugs