You are trying to find a logical reason for something that is illogical. He did all those things because he is an alcoholic. Alcohol affects the brain. Alcoholics don't think the same way non-alcoholics do. Even if they are not drinking at the time, their brain still does not function like that of a non-drinker.
It is doubtful you will ever get a satisfactory answer from him as to why he did the things he did. You will drive yourself crazy if you keep trying to get one.
You and his friends and everyone else may think he is hitting rock bottom, but you don't know that. There is another bottom under the one he is bouncing around on now...and another one after that. He hasn't hit bottom until he makes the decision that he cannot stand one more day living as he has been.