Suggest How To Treat A Child With Abusive Parents

Hi, I have heard this all year! Our neighbor has three children, one elder, one middle, and an elementary kid. The parents continuously have cussing squabbles, then the kids start to cry. The youngest one is most effected, and starts to scream and swear things like fuck or shit . And I know the kid and shes quite nice, but she gets sad quickly when her parents scream. I am very worried for the youngest because shes only a fourth grader. She is very quiet so how can I make her happy and forget things?