As part of the family, you really should call the man of the house "father"!

Why not call him Papa, like when you were little?

Pa...

No way! Can't I just call him Ky!?

But I think it's better to call your own father "father".

Uurgh... But I already have an old man!

Sin. From now on, call him grandpa.

Oh? Then Ky-san, shouldn't you be calling him father-in-law?

No way!!