I dislike eating. I'm not skinny nor fat, average. I'm also middle-aged. I don't like the process of eating, and I don't like to watch someone else eat. My son is the same way, as my father is. One of his quotes: "If I didn't have to eat to survive, I wouldn't bother". It's a disgusting process.
As your dad has this attitude it has passed onto you when you grew up, and your influencing your son. Spend some time with your son cooking strange and flavoursome items to help break the chain. You never know maybe you will find something you will like and it will bring your appetite back.
~Peace~