He thinks he does. I mean, when he says he loves them, I don't think he's lying. But it's an entirely self-serving, self-absorbed sort of love. Sonny's children are variously pawns, trophies, ego boosters, or excuses for self-pity. He doesn't see them as people in their own rights, but extensions of himself.
Then again, I don't think Sonny thinks of ANYONE as a person in their own right. Other people are generally property, enemies, or irrelevant.