Inheritance of car

My mum passed away 6 years ago, at the time she and my father were employed by my cousin(my fathers brothers son) . Prior to my mother passing away my cousin gifted a car to my mother and the car was registered in her name. In terms of my mothers will the vehicle was then transferred to my fathers name. Kindly advise in terms of shariah whether this was the correct procedure or should we have returned the vehicle to my cousin/or settled him in terms of the depreciated value of the vehicle at that time.