Get him to agree to a timetable for when the transaction will be complete. Presumably it is still costing you money to insure this car. If you can't drive the car you are still incurring an expense to protect property that you cannot use. If you do drive the car then you're running the risk of other things breaking. Either way you are still out of pocket for his benefit.

__________________
Jonathan

2011 Mazda2
2000 E320 4Matic Wagon
1994 C280 (retired)