Yes it is possible
. I did it too, I was on the lighter side quantity wise but I was very suicidal when I drank and mentally it was awful. The key ingredient is that you have to want it and you have to work it.
The fact that he already has a spirituality will be a big plus for him (lots of newbies struggle with the steps because of the God thing).
I have not gone to a retreat in a long time but they are really great and energizing. I m glad he enjoyed it, made new friends and got himself a sponsor.
Now that was my comment about his side of the street
You sound in a good mood but remember not to tie up your hopes and happiness to his. Keep the focus on Katchie whether he is doing good or not and stay away from his rollercoaster
