I've been abusing pain meds for well over ten years; this last go round was Norco 10s, 8 to 10 a day for over a year. I'm 13 days clean today. I can't speak to the other meds he's taking, how they interact with the Norco. I can offer an opinion - he will probably have a difficult withdrawal, but the 10 day break would probably work. Tapering is good, eventually he's just going to have to stop, make the jump. One very positive thing is, he is young, and that will help. Take it from me, the older you get, the more hellish the cold turkey detox process becomes. bmdad is correct - encourage him to visit this site and read. He will find support, practical advice about getting through the detox, and lots of stories - hundreds - about others who've struggled and made it.
I don't have any person experience with the rapid detox, but from what I have read, it's not the way to go.
I too started taking pain meds due to a injury. If taken long enough withdrawals are just part of the process. While taking them it's hard to know how much pain we actually have because when we decide to stop we get "rebound pain". It usually subsides after a week or two.
There's noway to completely avoid withdrawals even when tapering. Many choose to just go cold turkey and get it over with. Tapering helps minimize the withdrawals but it also drags them out. You just have to ask yourself if you'd rather feel uncomfortable for a month or while tapering or feel very uncomfortable for about a week.
I think spring break would be a great time to detox. That's what I would do if it were me.
You should try and get your son to come on here and post for advice. Even if he's not addicted he will still get so much of the needed support. Many of us were in his exact position in the past.
Best of luck to you and your son!
Brian