What if a family member steals the car of the deceased?

If you really mean to tear this family apart have the executor of the estate contact the police dept. and file larceny charges.

Theft is theft and stealing from the dead is the worst theft of all...

Have the executor of the estate call police and report the vehicle as stolen have said family member arrested for grand theft auto (a felony charge)..

Let said family member go through the process of being arrested,jailed,posting bail,and being arrained by the court...Then on the day of said family members criminal trial have the executor ask the court to drop the charges....thus teaching the evil doer a very good lesson...

However if said family member is not very well liked then allow the charges to remain and let them be convicted of grand theft....