Idk, I haven’t played the game since I was in high school, but I don’t really remember that Tidus’s dad was abusive. I thought he was just kind of absent/overly stern. There’s a lot of room between “star parent” and “abusive” for various levels of “not really a great parent,” and I don't remember Jecht being so terrible that understanding/forgiveness wasn't reasonable.

But I be might misremembering because 16 year old me thought Tidus was a whiny shit so I didn’t really take any of his problems seriously.