I stepped in and put my friend and her kid's father in their place when they were arguing in front of their son.
They had an attitude with me for a few days for checking them but later both separately came to me and thanked me for acknowledging the effect it was having on their child. They were so engaged in their anger they didn't notice the yelling and crying their son would do when they argued.
Children, regardless of their age, are very receptive to energies from their parents. Some people are like "oh they are only XX age, they dont know what is going on" but they really do.