Why would he want to change anything about this arrangement? It's working for him 100%. He gets to drink in comfort while you take care of all the adult responsibilities, childcare, financially supporting the family and everything else that goes along with being a grownup. All he has to do is go to a counseling session or a couple of AA meetings and promise to change every so often to keep you off his back and he gets to keep living his cushy life, bottle in hand.
I've learned a lot in Al Anon. One of the biggest lessons for me is that if I'm waiting for someone else to change so that I can have the life I want, then I will probably not ever have the life I want. I didn't do obviously enabling behaviors like buying him booze, but everything I did to keep our family running day to day made it really easy and comfortable for him to keep drinking.
I too was very concerned about what would happen to my ex when the kids and I left. I believed that he would literally die. He turned out to be much more resourceful than I would have ever given him credit for and wasted no time rounding up new enablers. Once he wore out his parents, he got married to a woman who had just enabled her first alcoholic husband to death. This was within a year of me leaving and he's constructed his entire life around being able to keep drinking in peace and comfort while someone else does all the icky grownup stuff for him.
I do have to tip my hat to your AH. That moving out with the tent thing was some pretty epic manipulation. Even my ex never took it that far, and he pulled some doozies. Sorry you and your daughters are dealing with this mess. I hope you are able to find some peace and clarity.