I've had nights like that. Some people are binge-drinkers like your friend. They get really drunk, make a fool of themselves, and wake up with a hangover full of regret. They then may not touch alcohol for another month. I have friends like that.
What separates me from binge-drinkers is I wake up the next morning and immediately start drinking again. I will drink alone for a week, 2 weeks solid. Every morning I'm waiting outside the liquor store for it to open at 10am along with the other alcoholics trying to hide the withdrawal symptoms.
My friends may see me drunk and stupid on a Saturday night but they have no idea that I will be off on a 2 week bender of around the clock drinking.
I'm mid-40's and the fact I am still capable of drinking like this is concerning to say the least.