Memory loss and infrequent eating can be symptoms of lots of things but they can certainly be symptoms of increasing alcoholism, but if you've kicked him out I assume you already have tried everything to get him to listen.
Sometimes, no matter how much we love them, they can be set in that self destructive course, and we have to detach with love, unless we want to be continued to be dragged along for the ride.
I'm sorry for your ex, but I'm sorry this is happening to you and your kids, too...
D