Oh my goodness, what a terrible nightmare.
Your children are being deeply affected by being exposed to someone they love, and their dad, basically committing suicide slowly, in front of them. You must do whatever it takes to keep them safe, both physically and mentally/emotionally. Let your inner Mama Bear take charge for a bit. You and the kids need to live apart from your husband for now, let him be committed, but do whatever it takes, NOW, to get those kids away from him.
It's the horrid reality of alcohol, that someone we love and have fond memories with should turn into someone who loves alcohol over all else. Pack your boxes, get friends to help out, and move. Who knows, maybe he will be one of those who turn around, but for now stand clear while he capsizes.
I send you big hugs. Hang in there, Mama Bear!