In my day, professorial alcoholism was a given. In your case, in vino veritas. Instead of getting the poor bastard fired for telling you the truth, you young jackanapes should have gone to the dean and told him that the course was academically worthless and demanded your money back without involving the dipso Professor.
Why not start attending MADD meetings?
I was in my 30’s going back to university for career purposes and I resented my time being wasted. The instructor had no business in the classroom. He needed to be in treatment.