It wouldn't be prison, it would be county jail. His crimes are misdemeanors and sentences are less than a year. State prison is for serious and violent felonies, prior felonies with 'strikes', and 'specific enhancements' (high level financial, certain weapons crimes, certain sex offenses). Technically both are absolutely no alcohol, but from what I understand state prisoners 'have their ways' of getting it or making it. I don't think it's too prevalent in county jails, most inmates there just want to serve their time and get out.
Assisted livings are another thing. The privately owned one my mum was in did serve wine only at their 'holiday dinners' but it was up to the families and/or the resident's doctor as to whether or not a patient was allowed that one small glass during the dinner. At my aunt's since the facility was part of a larger retirement community run by a religious denomination, it was 'tee total'.
The problem I foresee (at this point) is that he is still 'with it' enough to understand where he was and he'd raise holy hell. I don't mean violence, but that he would be very loud and very continuous in saying he didn't want to be there. I mean, I've actually asked him if he would rather be in a place where his needs were provided for, his room was cleaned, there was AC and central heat, and there were other people around. A resounding 'no'!
It's really horrible when someone is 'bad enough' that they shouldn't be living alone, but still 'with it enough' to have legal capacity. According to the APS SW, choosing to drink yourself to death doesn't mean you lack capacity. Certain behaviours when drunk might, but the problem is that they sober up and 'regain' capacity.