In my experience, a car is insured, not a driver.

Cause I used to drive other peoples cars a lot and then when I started paying for insurance I had to learn a lot more about it.

If Mike wrecks my integra, its still insured by me. No one stole it. Its still my car, its still covered.

At least that's my case. I'd call his insurance co. Especially if you were driving for him since he was "unable to operate a motor vehicle"