Am I Being Unreasonable? Original Owner Wants Car Back

As the owner of a car that my dad ordered in 1971, I can not explain what it means to me to have it. He has been gone for about 5 years and every time I do something to it, I'm wondering, how would dad do this? There is absolutely no way I'm selling! At the same time, YOU own the car. If he wants it back bad enough, he will find a way to pay you what you want. Otherwise you don't owe him anything, imho