Were they a named insured in the Household? By most companies, if you are rated in the household, you may drive any vehicle in HH. Yes, coverage should still apply to the vehicle however I would try to get the title of the car changed out of the name of the deceased party's name as soon as possible.
Insurance follows the car, not the driver. As long as the car is insured and you have permission from the owner to drive it, you are covered.
The at fault driver always has the primary liability for the damages they cause in an accident. (The guy who rams the other guy).
The Owners Vehicle Policy offers primary first pay coverage. Any policy carried by the driver would invoke as secondary coverage.
It depends on which company your uncle is insured with, but typically with a standard insurance company you have to live in the household to be a listed driver on the policy. This is regardless of your relationship to the primary insured. If you are not listed on the policy as I driver you are still insured to drive his vehicles as long as you have permissive use.
The definition of a primary driver is the main person who drives a vehicle. Other people who sometimes drive are secondary or part time drivers.
P.S. The insured driver is found at-fault with witnesses. The uninsured driver is worried if his license will be suspended or facing any penalty for driving the his parent's INSURED car.
No direct answer, as this all depends of the level of cover of the insured driver.
As far as states go I know in Utah it is the vehicle not the driver that is insured.
Usually the insurance policy of the owner of the car is primary and then if the driver of the car has a policy of their own then it is secondary.
They'll go after the car's owner first. IF the driver has an insured vehicle, it would be secondary.