Seriously? You mean sleeping in the backseat didn't work? If you fall asleep sitting in the driver seat where you may have had an intention to operate the vehicle, I could see it. But if you're using the vehicle as shelter and you deliberately went into the back seat and went to sleep, you did not have an intention to operate the vehicle. There is no "realistic" chance of injury to anyone if you're sleeping in the back seat. What about people who live in the cars/vans? If they drink too much do they have to go somewhere else?
That's why it's referred to as "care and control of a vehicle", not "occupying a vehicle with intent to drive."