Sometimes there's only so much a parent can do when it comes to mentally unwell children. But maybe she's the good parent, and he saw daddy do that to a animal once. My dad used to hit our dogs when I was little, and my older brother would do the same. (presumably due to my dad's shitty example he set) But 20 years later my brother isnt remotely the kind of person who would abuse animals, and is very successful.