Truck debtor is different from Registered owner?

My father-in-law just passed away. He didn't have many posessions, but we just now realized he has been driving a brand �ew truck. When we checked the registration, its registered i� his name. We did a lien search, and have determined that the truck was financed by a lady friend he had for a very short period of time, and who was out of the picture when he passed away. We are confused on what to do. We realize the truck technically belongs to this woman, however we do not really want to give it to her while its in his name. Any ideas?