Hi,
I'm sorry you are so worried.
What I need to try to do when I am wondering 'what if' type questions regarding someone, is to take myself out of it and leave it to them. It's not easy, especially when we are very close with the other person.
The best thing I can do is go to meetings, come here and share and learn as much as I can about the disease and about my own condition of codependency.
My son needed meds a few times and did abuse them. He also used them at other times as directed. If someone is going to use or drink...they will do so regardless.
For some, a drink starts up the drugs and for some a drug starts up the drink.
Either way, he has to work this out for himself and I hope he will.
Enough about him... how about you? Do you attend any anon meetings? If not I hope you will try some and also continue to keep posting. It helps me so much to come here and find (sadly) so many who understand.