Am I Being Unreasonable? Original Owner Wants Car Back

And apparently the Dad didn't have any regrets selling the car back when he did. Seems it wasn't important enough to any of them back then for the Dad you give or sell it to them at a discount family price. Just seems fishy to me.
I think the old adage "You don't appreciate what you have until it's gone".......They weren't memories back then. I have my Dad's 1987 D150 that he bought 6 months before he died. I drove that truck for 15 years as a daily driver. Wasn't sure what I was going to do with it when I bough my new truck so I parked it in '02.......I was going to do a body swap with a Cummins truck but am glad I didn't. When the Demon is done, this ones next........Today, I'd get rid of the Demon before his truck. That's how important this is to me. BTW......If someone else had it, I'd pay whatever they would want.