So this is anecdotal at best but these are my observations of kids/peers around me. In my normal everyday life and my time in juvenile justice. The eldest really only goes 2 ways with the less stable, less seen parent. One is they see that parent for exactly who they are and may even see them in a more negative light than most of the world, lacking some empathy or grace that they would give literally anyone else if they behaved the same way. Or they put that parent on a throne of imaginary glory. The problem with the latter is once that parent falls that child won't pick them back up, and it's a very very hard fall because the allusions about that person the child created become glaringly obvious and they essentially break their own hearts in the process. S12 is still young enough to idolize dad because he isn't synthesizing everything in front of him, but I doubt highly he'll still see dad that way by the time he's 15.

Also not to contradict May here, but having more first hand experience here, napping and passing out, even as a sound sleeper are two very different things. I have zero judgement for people who nap with kids around as long as they aren't' under the influence. I'm not a napper but if you have kids who actually let you nap my god take it. But I would put money on the fact that that isn't' what happened here. If he wanted that nap he could've waited until the kids were gone. They would've in fact been gone sooner had he not laid down. The way I see it is exH may have made it into the bed to lay down vs just dropping on the kitchen floor but it doesn't make it any less passing out. The fact that he didn't once hear the phone ring, or wake for the kids after multiple wake up attempts he was very likely passed out. Him sleeping poorly due to the drinking or the depression or some fun combo is probably why he aims for drunk enough to pass out. Just to get some sleep, even if it's crappy drunk sleep.

As far as escalating behavior. My exH is functional as well. Not one DUI. Never lost a job. Pays his bills on time. Well now, not when we were together. But being functional doesn't' really change how people with AODA issues behave. Your exH now that he has no reason to put on a show or hide his drinking, will devolve. If you notice this little passing out incident didn't happen the day the kids got there. It happened the day the kids were leaving. He thought he'd be fine because you were coming to get the kids and they were leaving any way. He will rationalize any reason to start really drinking when he can. Honestly he will very likely hold on to his job and stay somewhat stable as he probably has a pull to provide. But nights and weekends, its no holds barred. He's in a phase in his life where he thinks he can be what ever he wants and you were just holding him back. He's in a phase where he felt like you were stifling him. Not realizing that he was doing those things so that you wouldn't see how bad the drinking was. He likely is thinking he's like 20 again, and he's just having a good time and letting loose in what ever way he pleases vs the reality that you, a MR and family life were keeping the drinking in check. I know very few if any addicts who just kinda maintain the status quo. Maybe I'm wrong and your kids will be lucky enough to have a dad who is one of them. But statistically, and my gut, says it's only going to get worse.

My exH maintains a kind of a status quo I suppose. Best guess here is yours will likely follow the same pattern. My exH will get deep into his addiction. Things will start going really badly. Struggling at work. Hurting himself (not on purpose). Breaking things. Losing things. Fighting with everyone he knows. Reality will eventually set in and he'll do some AODA counseling, maybe go to a few meetings, maybe even work a step or 2, quit cold turkey and tell the world how many days sober he is. And things will be ok for a little while. And then he'll start again. A beer here or there and within a few months he's downing handles of cheap vodka over the weekend. And we cycle through this over and over again. With distance it feels like he's just kind of a constant level of addict. But D18 and I have the gift of distance. We've had that for some time now. You my dear and those sweet littles of yours are in the thick of it, and likely will be for a while. Its why I push so hard for the Ala-non and Ala-teen or some kind of AODA counseling for loved ones. You are going to need that kind of support, so will the kids.