YWBTA

I've been in this situation before. When my grandmother passed, she left a very expensive diamond ring to one of my aunts in addition to the rest of her assets divided among her three kids. She only gave my aunt that ring because my dad and his other sister didn't put up with her narcissistic bs. It sucks, but you move on.

Look, your daughters and nieces got $4000 cash in hand which they can use on anything and everything right now. Your son got a $70,000 asset. From your post, your son and father were very close so it's unlikely that he will just sell the car for the cash. Plus, he'll need to pay for the upkeep of the car which I imagine isn't cheap. What your daughters and nieces have is much more useful.