That’s what he grew up seeing so that’s wha he thinks it’s normal. I grew up with seriously abusive parents that abused me physically, emotionally and verbally so I grew up thinking it was normal to be scared shitless of making your mom angry or just used to your dad insulting and humiliating you and basically never being around. When I finally left for college and friends invited me to their houses it was a huge shock to see their parents loved each other, that fathers didn’t usually insult their children and mothers didn’t curse or hit their kids with whatever was closer to them! My mind blew up seeing siblings getting along and loving each other!