Thanks for bringing your question to JustAnswer.
To the best of my knowledge neither the AMA or NIH have every been able to specifically prove or say one method of recovery is better than another. AA works for many,many people. Others respond best to in-patient, residential treatment. Some respond to medication. It sounds as if your son is doing a combination of AA and residential, which is a sound idea. Here is a link to the latest research articles by the NIAAA branch of the NIH: http://pubs.niaaa.nih.gov/publications/arh334/toc33_4.htm
I could not find any statements by the AMA about preferred methods of treatment.
The hardest job you will have as parents is to let go of the idea that you can come up with a magic bullet that will cure his disease. It is incredibly painful to watch our children making destructive choices. One of the best things you can do for yourself is to go to Al-anon to learn how to deal with his alcoholism and also it's effect on you. No one can make another person get or stay sober. It is up to him to suffer the consequences of his choices, and to re-build his own life. He will make mistakes along the way--dating so early in recovery is likely to turn out to be a mistake. But he will only learn by making the mistakes and learning from them. For your own peace of mind it will really help to have a support system of others who have dealt with this disease in their family. They won't talk about treatment methods...the focus is on how to cope with his illness and his decisions.
I know you were hoping for a piece of research to prove what he should be doing, but it does not exist. There are many treatment options, because people respond differently to each one. Think of it like heart disease--some people are able to control it through diet and exercise, some need medication, and not every medication works equally well for each patient.
I hope you will give al-anon a try. It will also help you to relate to his 12-step approach to recovery, as al-anon is also based on the 12 steps. By joining him in recovery, you'll be teaching by example.