You would be amazed at human capability. I used to be a Critical Care physician. I once treated a nurse who had a blood alcohol over .700. Couple of days on the ventilator and some vitamins and he was good to go. Before discharge I asked him if he wanted help with his drinking. He replied No, he was doing fine partying on his own.
I wonder if Darwin's law of natural selection ever caught up with that young (presumably) man.