Guys, don't be too hard on him. He took some caffeine (stimulant + depressant = neutral, right? that's how chemicals work in Science. it's like Rad-X in Fallout 3) and didn't drink for like, a whole hour, which means his blood alcohol level got reset.
While he may have been unable do crazy stuff like "typing the English language correctly" upon returning home, that doesn't mean he was incapable of performing the little things, like operating a piece of metal weighing several tons, filled with combustive liquid, and moving at lethal speeds, while on icy roads in the middle of the night.
Besides, the guy could have lost his job. Possibly losing your life is one thing, and the risk of having to explain to grieving parents why they lost their son to drunk driving is a thing too, but the possibility of losing your job is just in a different league.