I would probably not serve alcohol at a dinner if one of the guests asked me not to and I wanted them to be there. you have no idea the conversations they may have had about that. FWIW I variously gave up alcohol, removed it from the house etc to support xAH or to show him that fun is possible without alcohol. never made any difference, he always drank in secret throughout anyway.
He spent christmas day with us, I had a glass of wine with christmas lunch, and some fizzy wine later. Because I wanted to. He had brought his own supplies and was drinking throughout the day in "secret". I knew he would drink, and I was inviting him over so the kids could spend christmas day with both of us, so it didn't surprise me, annoy or upset me. His behaviour was fine, as I have been able to recently draw and enforce boundaries about how he acts towards me, and he was pleasant and played with the children, so there was no point in bringing it up and ruining the day for the kids.
I have learned that it doesn't matter what I or others do regarding alcohol, ex will drink, a lot.
so yes, the car thing, if he drives the car and you're making the payments, could you sell it?