You know what’s funny? My dad’s “family name” used to be my last name. It was like that for years. And then when we moved to the US…my dad decided to make his “first name” as our last name. In the US…it’s the “family name” that’s used as the last name (which is how we previously had it).
Anyhow, I asked my mom about it years ago, and she said that in Pak…the view is that the having the father’s first name as a last name…makes a direct connection between the offspring and the father. So, I guess my dad decided to uphold the tradition.