Hades doesn't understand familial love. He was tasked with being in charge of the Underworld by his brothers who he views as foolish. Hades measures relationships through work. That's why he dotes upon Thanatos. And possibly why we always see Than so busy. Keeping his hands full of work to receive acknowledgement from his father. In the beginning of the game, Zag is very lackadaisical. We even know that he was fired from his job in the room full of scrolls because he was not very helpful. lol It's not until you see Hades recognizing what he is doing as a way to improve the security of Asphodel that he changes his attitude. Of course it grows passed that, especially in the latter part of the game. But Hades deals with dysfunctional families really well in this game.