Taking Possession Of A Gift

A few years ago, with my grandfather’s approval, my uncle took the responsibility of handling my grandfather’s financial matters. At that time, although my grandfather was 100% mentally well, physically he was disabled and needed a carer. My mother (his daughter) took on this responsibility. My uncle gifted my father my grandfather’s car in lieu of recompense for taking care of him. Now my grandfather has dementia and isn’t in a state to make decisions, so it’s not possible to ask his approval of this gift. Was this “gifting” of the car correct? My father has since passed away. Will the car become part of my father’s estate, or does it still belong to my grandfather?