For what it's worth as a (former) addiction counselor, and a pretty hardcore one at that, I concur.
If Rob ended up at Caritas while I was there (or for that matter, one of the other 'old-time' counselors), the first thing would have been to strip every distraction. You can watch the 6 o'clock news at Caritas unless you're the cook. I would have made him the assistant cook (so, no responsibility but to follow instructions from the cook, who in turn follows instructions from the -older- resident in charge of food). No news. In fact, I might have advocated for no news for anyone, lest he retain some kind of star-appeal. I would have done anything I could to ensure that the fact that he was famous and the mayor was actually a burden on the other residents. As gently as possible though, because I wouldn't have wanted to feed an excuse to leave.
I wouldn't let him speak more than a few words in meeting for a while. Maybe a month or two. Just listen. Occasionally express a feeling at the Monday night "feelings meetings", but that's it.
After a while the nothingness would probably start to break him. He'd talk about missing his kids. And then the big hammers would come out.
The endgame would be to demonstrate that he has no other responsibilities in life that actually matter besides them. Damage has been done, but it's not too late -- what happens next is up to him. With the strong boundaries that addiction is incompatible with being a good father -- and given what has happened up to this point, holding elected office is also incompatible. For a "normal" person, it can be done with understanding and scheduling, but in his case, he's had that opportunity and it hasn't worked. Maybe in another 4-8 years (I'd choke while saying that, but if he were my client, I'd say it). But first thing's first. Him & his kids. He can still be a hero to them, if they come to understand that he dropped *everything* to be there for them.
But if his addictions & career continue to come before them...
ETA: the older residents would have taken care of a lot of this too. The "star-appeal" would wear off pretty quickly on them if it became a distraction and he didn't tow the program line. We used to have a resident who was quite wealthy at one point -- and I recall, when he was placed on barn duty, an older resident saying "Look, from the penthouse to the pigpen". I can just hear it now "Who do you think you are? You're mayor of the bathrooms now".