If a friend borrows your car without permission and gets into an accident will his insurance cover it?

First of all a friend does not borrow your car without your permission- if they used it without your permission they really arent your friend and they technically stole your car- Unauthorized use of a motor vehicle- Their insurance will cover them only if you file a complaint with the police stating that the person did not have your permission to use the car. Otherwise your insurance will cover the loss and your rate may jump or you may get cancelled. Your call- depends on how much the claim is and how good the friend is