i'm a recovering addict who has been through several detox and rehabs, and i think like bigsis say, there is no cure for addiction. rehab is just the start, it teaches tools of recovery gives space for clearer thinking, space for getting the system cleaned but the real work began after rehab or detox. i found that i had a lot of painful core issues that i needed to work through, for me, using the 12 program helped me to do that, taking away my need to medicate the pain of my past with drugs and helping me to become a more healty person.
i'm sure that there are other methods but i don't know of any that worked for me, there is a big difference in getting clean and getting sober. the 12 step program was a live saver for me. i pray that your addict will find his way to sobriety but in my opinion, even if he manages to stop using, the problem would be whether or not he can stay stopped. clean does not equal sober living that comes with commited soul searching.
i guess the answer to your question would be that unless the addict is commited to getting better, nothing will work.keeping you and yours in my prayers