The first thing that struck me is that....
If all is running smoothly, there is an hour 4:30-5:30p when you can stop for a while and this is when you begin drinking. I’m wondering what else you can do in that hour besides drink? Go for a walk (I find that when I walk, without music and alone, I can think more clearly and I can plan), go to the bookstore, go for a nice drive, buy yourself something, start your Christmas shipping, visit a brother or sister?
I to have a sp[ecial needs kid and a younger one. My husband works late and suffers from depression and inertia to varying extents. That kind of stress can lead you to poor coping if you don’t have time to figure it out.
When you do stop drinking again, you should probably work on the parts of your life that are not working well at all (the work division at home, the marriage, respite care for your special needs kid?).
Not sure NAC has been studied enough to help a lot in alcohol situations, but I don’t think it will hurt so try it if you like within the recommended dose. However, don’t expect it to be a magic bullet.
Bottoms line is that I think you have some opportunitites to take advantage of if you make the time to think about it.
Wish you all the best in your recovery