Grandpa
Noun and の adjective
そふ
う〜ん、何て言ったらいいのかな。僕の祖父は単なる気分屋なんだよね。機嫌がいい時もあれば、悪い時もあるっていうか。だから、あんまり気にしないで。
Ummm... what can I say? My grandpa is just a moody kind of a guy. He has highs and he has lows. So, don’t even bother him.
Your ancestor father isn't your father, it's the father that came before your father's generation, your grandfather.
The reading is all on'yomi, which is great for 祖 but not as great for 父. To remember that this 父 is ふ, just think about how much of a fool (ふ) your grandfather was, even if he wasn't.