Purchasing a car from a private seller. Nightmare.

Update: went to DMV, no problem at all. I also heard back from Bob. He did contact his mechanic nearby who he has sent business to for 15 years and called in a favor. He is arranging to pick up the car later this week, make the repair and deliver it. Bob committed to seeing this through until it's resolved and provided the mechanics number to me. I'm feeling a lot more positive about this whole thing now and optimistic!
Good to hear!