Mom my friend at school's parents always fight, and sometimes her dad hits her mom. What is that called

Thats called domestic violence honey. It's a real problem in the united states.

Domestic violence? What is that? 

Well honey, domestic violence is when someone inside a home is upset and they take their anger out on someone else inside the home. 

Well if her dad is like that then all men must be like that. I hate men. 

Not all men are like that. Did you know that 15% of all domestic violence victims are men? And male victims are less likely to seek medical and police help so that number could be different? Domestic violence can happen to both men and women. You cant hate all men because one or two messed up.

But mom, how do you prevent domestic abuse? How to you keep an argument from spiraling out of control?

Well first off you try and see your partners point of view. put yourself in their shoes, then you both keep calm voices and dont start yelling and shouting at each other. And always keep your hands to yourself. You just need to respect your partners boundries and make sure to keep your anger in check.