Yeah, he talks about the things his father did, but it's not really whining. In fact, I'd say if anything, the way he deals with it is both mature and confronting his issues. That's why when you fight Jecht, he's still angry with his father, but he's also sad that he's going and loves him.

Also, Tidus IS pretty stupid it at times

"Macarena Temple."
"Aye!"