Why was Michael hiding in his sons car?

Near the start of GTAV, Michael, Jimmy's dad is hiding in the back of Jimmy's new car when it gets stolen by Franklin and Michael pops up with a gun when you're half way down the road. This never crossed my mind before but I recently started the game again and noticed it and couldn't understand why Michael was under a blanket hiding in the back of the car?!

The guy who sold the car to Jimmy wanted to get it back so he sent Franklin to steal it. The car dealer and Franklin were the only two people who knew the car was getting stolen so Michael wouldn't of known anyone was coming to get it, so why was he in there?

Michael knew about the financial situation surrounding the car. Consider how much he understood about Simeon's business practice, Michael obviously did his research. He also came from a criminal background, where he was used to dealing with other criminals as well. Remember that in the mission prior, Jimmy was just at the dealership purchasing the vehicle. This implies a very short time frame (same day or possibly next day) that the car was to be repossessed from the purchase time. Put two and two together, and it's not too much of a stretch to say that Michael took a good guess that the car would be a repo target around the time that Franklin took the car.

Maybe he was drunk and went for a nap in the closest thing to hand?