Thanks for the warm welcome, everyone!
I haven't read Codependent No More yet, but I do have a copy of it on my bookshelf for when I am ready for it. I have been doing some of the daily Al-Anon readers. And I just finished a memoir about alcoholism -- Dry by Augusten Burroughs. It was very powerful. And I think it was helpful for me to read about that author's rock bottom, and the bottoms of other people he met in rehab. Bottom can be so, so, so much lower than I could ever imagine it would convince someone to stop drinking. Addiction is a unbelievably powerful monster.
I have heard from my ex's parents that he did go to detox and that there is a counsellor there trying to find him a spot in residential treatment ASAP (preferably, straight from detox). He stayed at his parents' place for about a day before he could be admitted into detox and they thought they'd hidden their booze from him. They were surprised to find he'd drunk over a dozen beers, leaving the empties behind in the room where he'd been staying, and yet showing no signs of having drunk while they interacted with him. His tolerance for alcohol is really something.
Today, I am much more ok with everything. I am glad to get news about him and also glad not to have heard directly from him yet. When we last spoke, he said he would not call me again until he was better. We didn't set terms as to what better meant but it implied at the very least sober and not expressing suicidal thoughts.
I truly wish him well.