Auto Insurance: Parent Died and Auto Was Not Insured

My question involves insurance law for the state of: illinois
My sister died recently after a short hospital stay. During that time, one of her 3 sons started using her car to go back and forth to the hospital.
Recently after finding some of my sisters papers, I discovered that the vehicle insurance was not paid for months because of her illness. What should her son do with her car?

Auto Insurance: Parent Died and Auto Was Not Insured