What if the friend was lying about never seeing the car? What if the friend borrowed it?The whole "Friend authorization" thing is a complete red herring that I don't see has any legal basis for an argument because the friend NEVER TOUCHED THE CAR. It would be the same as one of you telling me I could drive your car, that it is in the street in front of your house, then telling me I'm responsible for damages to it from a hit and run, even if I never actually used the car.
Was it stupid to leave the car unlocked and with the keys? Yes. Does that change the fact it was stolen? Nope.
If one doesn't have funds for a lawyer I would be contacting the insurance company and also making contact with the people listed as company contacts. Someone can step in and o the right thing here, and it shouldn't take a lawyer to make it happen.