Rehabs aren't a cure, they are a training place to help recovering addicts find tools to keep themselves on a good path, or to find their way back if they stumble.
Let's hope he finds his way back. He knows what he needs to do, so far his actions sound good. Going back to rehab may or may not be the answer, but there are lots of other support groups out there where he can find support and help.
I'm glad you are taking care of yourself through all this. I know the gut kick feeling when relapse happens. But I also know that having our own support in place and working our own program will help us through the dark days.
Hugs