You can go to the local vehicle management office to apply for sealing business. Tell him not to continue using it. You can also go to the vehicle management office to report the loss of the vehicle directly. You can just go through a new set of procedures and then go to court to sue him. What to do depends on whether you want to give the car to him or take it back yourself. If you want to give it to him, explain the matter clearly to him first, otherwise you will do as above and make him unable to use the car. After all, he is the guarantee for the loan. Even if you don't repay the loan, the bank will come to him directly after you don't repay the loan.

This matter is easy to handle, so don’t worry~~