The cravings come and go maybe forever. How to stay clean IS THE PROBLEM. Look in the phone book (usually in the front) for addiction help, groups, counseling etc.
Day 5 is very early and only the really nasty WD symptoms are over. Try to get him interested in his own treatment. It sounds like you set up a type of detox for him. Eventually he will need to do this on his own and with support from other people as well as you. You've done a great job!
Interest him in reading the posts on this site. That's a good place to start.
Well yes, absolutely. My wonderful wife has nursed me through WD so many times and the most vulnerable point is definitely when I am just barely feeling better, just enough so that I can get out and score. The fact that she eventually has to go back to work and I'm home alone plays into it as well. We have had to do ridiculous things like having me give up my truck keys and my wallet and checkbook at that point and have friends check on me to make sure I was still home. Sometimes all that sort of worked. But if I read you right and he was injecting oxycontin 3 times a day he is definitely going to come out of WD with intense, almost uncontrollable cravings. It takes a lot of hard work to stay off. Good luck.
I dont think the craving ever stops completely. He needs a hobby and aa meetings especially at his point in detox. Addicts are addicts and we will always be an addict whether we are using or not. My wife has detoxed me twice and the second time she did it was just as caring and loving as the first time. You being there with him thru out this will be very important. The cravings come on at anytime so having someone to talk to during this time is important. Also be careful with the cold medicines, especially the syrups. They are also addicting.