Consider this. For Yato, there is no way to defeat his Father without ensuring his own demise. It's even more painful when said Father is an abusive sociopath.
The flashback of Yato's childhood. He and Nora killed people as a "game" bringing their ears to Father. One of the panels displaying their massacres had Yato innocently wondering why a woman they killed had a person in her belly.
The little hints we get of what happened to Yukine when he was alive. His own father possibly killed him by burying him alive. Later on, we finally get to see what happened to his body: he just dumped it in a refrigerator outdoors and let it rot.
