It took him a long time to get himself where he is today. It will take a long time to unravel the mess.
i know it's hard but try to have compassion for him and his process. He has maybe only just begun to scrape the surface and is dealing with the more superficial hurts.
Sounds like what you went through runs much deeper and may be hidden under layers of denial. He may not have the capacity to deal with things on that level just yet.
From the extended serenity prayer
Grant me patience with the changes that take time, appreciation of all that I have and tolerance for those with different struggles
A short stint in rehab is not a magic wand. It's wonderful for your kids and you and him that he is on the recovery path. It would be lovely if it was the end of the story. It is not, it's another beginning.