What a turkey. (I totally used a different word in my head.) I'm picturing a little kid stomping their foot, hands on hips, yelling "FINE!" and sticking out their tongue.
Well.... Since there's nothing you can do to change his twisted little pout (I'd agree that removing the breathalyzer is a no-go), you could look at it as a chance for the kids to get up to an additional 6 hours of sleep. Yes, it'll suck getting up that early on Sunday, but the kiddos can go back to sleep once they're on the road. (He doesn't get that option - and I'm sure that'll get old.) The commute we used to do everyday was about 2 hours each way through most of the school year. DS slept the whole way in and the whole way out. He'd either carry out one of our pillows or one of his soft smooshy stuffed animals, so he could comfortably lean and sleep. Your kids may not be able to sleep the first trip, but once it's more routine (if it ever happens enough to BE routine), it'd be a nice little nap time.
Big hugs!