I am pretty sure your FIL will have to get the title assigned to him and then he will transfer the car to you. BUT he can possibly do this by giving you a power of attorney to deal with this issue.

You may have to send some documents back and forth so they can be notarized but it can be done. I am sure you will need a death certificate for your MIL.

This is worth a modest legal fee to get it done right, if for no other reason than to get it out of your driveway.