If the trust owns the car the trust owns the car and it is not yours. If the trustee reports the car stolen, the police will treat it as stolen. Work the situation out with the trustee, you don't want to end up in police custody because of a misunderstanding.
As a practical matter probably not, it is unlikely the insurance company is going to pay you with out what they are looking for. If the matter becomes a law suit your boss is certainly going to hear about it when discovery is sent.
Your next of ken would be entitled to your property. Given what you describe your mom is likely your next of kin. You might want to talk to someone, it just sounds like you need someone to talk to in general.