The guy is 23. By now he should know how much he can drink.
As others have pointed out, yes you can black out and not remember the next day what you did, but alcohol will NEVER make you do stuff that you would never dream of doing sober.
Yes while beeing drunk lots of people end up having sex with their best friends, but thats allways because they have toyed with the thought while sober.
So this disgusting asshole molesting her is a pretty clear sign that he has thought / dreamed about that while beeing sober.
His lame ass excuse is disgustning. He should own up, stop drinking and start seeing a shrink.
He has serious issues. And I have a feeling this is not the first time he has done shit like this while drunk.
Really great that the girl spoke up. Must have taken a huge amount of courage. Hopefully her example, will give other victims the push to come out with these things.