"However, you should be prepared to be named in the very likely chance that he will be sued by the other party and/or their insurance carrier. The problem that you will have is in trying to defend against the assumption that he had your permission at the time."
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My response:
Excellent answer, Steve. You are absolutely correct. She knew her son was unlicensed, and knew her son was a criminal. Although she was "asleep", she made her keys readily available for her son to take. Knowing the facts as she did, she had a duty to keep those keys away from him and, by making the keys available, she gave him "implied" permission to use the car.
Similarly, "special circumstances" may exist when an ordinary vehicle is carelessly made available to a person incompetent to drive. [Richards v. Stanley, supra, 43 Cal.2d at 66, 271 P.2d at 27 (dictum)--suggesting owner might be liable for leaving keys in unattended car in front of school where owner might "reasonable expect irresponsible children to tamper with it" [Murray v. Wright (1958) 166 Cal.App.2d 589, 333 P.2d 111]
She's on the hook - - big time.
IAAL