Hey Rev! I see that you started with us in 2014. You had a brief reprieve with her where she agreed to only 2 drinks a day. That steadily went by the wayside. Now she's at 3 bottles a day.
My advice would be to continue with Al Anon, and work the step program if you haven't yet. As for an intervention.......Every once in a while I do see where they have been successful (rare, very rare), most of the time they aren't.
I know you are still looking for a way to "fix" her. We have all been down this road. There is no YOU fixing her, only SHE can fix her. Since her current response is" She doesn't want to quit." I'd believe her. At least she is truthful. Her alcoholism is progressing. She is drinking early in the morning, all through the day, passes out and drinks more.
If she is able to remain abstinent on the job its not for long is my guess, in fact it might be part of the reason she is considering retiring.