Parents are fighting....?

At around 8pm today when my dad got home from work he and my mom started fighting because my dad didn't want to eat why my mom made that day. They fought in the kitchen, my dad grabed my mom and started yelling at her and saying how she doesn't do anything around the house, that got me upset because she has to clean the house, cook, look after my sister and me, And when my dad was yelling at her she started crying (it looked like he was gonna slap her) and then I started to cry because I HATE to see my parents fight and I don't like to see my mom cry. Also yesterday when my mom was at work my dad snapped at my sister because she didn't finish washing the dishes. He started saying mean stuff to my sister like that she's "useless" and stuff like that and he made her cry. Now I'm super scared of my dad. I was always "daddys girl" but now I'm afraid to even go near him. So my question I what should I do if my parents fight again(defiantly a possiblity they will), and what should I do about my dad???