He started talking contradictory gibberish, and was otherwise unresponsive, so they took his car keys.
That's being a good friend.
March 6th is 'the morning after'; where they'll check he's sobered up and understands the consequences of his actions.
That's also when they have a chance to transition from 'good friend' to 'car thief'.
I support this action; I believe it was the right choice at the time, but the onus now is on the witnesses to provide a clear, simple path to a roll-back.
No hurdles, no hoops.