I watched only a couple minutes of him hitting her because I'm at work, but I find the situation confusing. Disabled how? Why seven years later?
Maybe I'm just used to this kind of behavior and I'm not as shocked, idk. My parents were violent and always screamed, my mom hit me like this from time to time.
Bad parenting for sure. Unacceptable.
The daughter has ataxic cerebral palsy: http://en.wikipedia.org/wiki/Cerebral_palsy#Ataxic