Hi Rosie,
Each situation is going to be different. Some people recover from alcoholism and want to return to their lives as they once knew them. Others (many who have been struggling their entire adult lives) don't have a frame of reference on *before* and need to start anew and learn who they really are, what their values are, and what they want to do with their life.
I know that may sound dramatic, but for someone who has been struggling with the alcohol demon for 10, 20 years - the change is truly that dramatic.
I applaud your friend for taking his sobriety this seriously. With his level of activity focused on his own recovery as well as helping others - it shows that this has become the top, if not #1, priority in his life.
It is very possible that he needs to break from the past in order to break free from old habits and triggers. This is nothing you caused, you can't cure it, and you can't control it - it is just part of his recovery, which he has to own (and sounds like he is doing just that).
Let it go, give him time to heal, and if it was meant to be, it will happen.