A good son would sit with his dad in C and suck up the fact that he's spoiled to F. Afterall, wouldn't you rather spend more time with your dad than a complete stranger (even IF you are sleeping)?!

You'll have plenty more opporutunities to fly F in your lifetime.

The only appropriate alternative to my suggestion above is to let your dad in F and you take the C seats. That's the proper thing to do.