TheLadyB...
Not the relaxing Friday night you envision at the end of the week.
There are alot of good suggestions being shared with you.
I understand you not wanting him to be driving, however, I suspect he knew that you would probably drive him back to the bar if you prevented him from driving.
Do you think if you told him he could drive, but, you would call the cops, that you could follow thru on that? Is there another boundry you might be able to put into place?
As he doesn't drink during the week, maybe that would be the time to tell him what your boundry would be.
I am sure this is hard, as he probably will do anything to defend his drinking, so, he can keep feeding the demon.
I am glad you aren't drinking, and can be the sober, healthy parent for your son.