These are not questions actually for you to answer, and I'm so glad he's ok, but...
What in the do? A litre? In 30 minutes? Stupid, but impressive, not gonna lie. But why? I had a friend who drank at least 2 litres, but it was over a few hours and she barfed all over the fing place. I had another friend who drank a litre, but she was just pure steaming. It never even crossed my mind to call an ambulance either time. At least he was with more sensible kids than I was at 17/18(& the rest). Oh, to have the bounce back capability of a teenager/young adult again. I miss those hangover free days. But a litre of vodka for a non-drinker? Jesus. Legitimately, is he ok? Emotionally? Was it showing off type s or is something going on? But you got to ride in the front of the ambulance? That's pretty epic. Did you get to have the lights on and the cat screaming? Did it go fast? Do they listen to any music? Proper fancy taxi.
I feel like hangovers should be opposite - the young should suffer them and we should become immune as we age.
Anyway, silly lad! But thank do he was with people who didn't just leave him or duct tape him to a lamppost and do off.