Originally Posted By: olivant
Right TB, It's not until II's flashback scene that he refers to him as Pop.

Also, to add tot he above, Sonny tells Tom "... he's not your father." Considering the bond between Sonny and Tom, that's quite a cold thing to say. At the least, it's unexpected.

And why is that? I'm really curious about that matter in case anyone wonders.

I definitely agree on that. It is quite a cold thing to say.