childcare... Help!

I know this isn't period related at all but a lot of women on here are moms and I could really use advice. I nanny for two boys, ages 7 and 10 years old. The parents are recently divorced and everyone is having a terribly difficult time adjusting. Recently the younger boy has been misbehaving and not listening to me. I understand he is acting out for attention but it is beginning to get dangerous. If he doesn't like what I am saying to him (i.e. It's time to do homework, you can't call your brother an asshole for wanting to play with you, you can't have candy for dinner) he will either run out of the house or hit me. On ovccation he has run into the street or into a wooded area behind his house. I am worried for his safety as well as his brother's safety. Today he got so mad at me because I reprimanded him for kicking his brother in the head that he punched me in the stomach. I have talked to both of the parents about his behavior and violent outbreaks but nothing seems to help. He has told me and his parents that he doesn't care what any of us has to say because it doesn't matter, he won't listen to us anyway. I feel the parents are being too lenient because they feel guilty about the divorce meanwhile I am suffering the consequences. It is really difficult to discipline a child that isn't yours especially when the parents don't support you. How do I better control these dangerous situations and get him to listen to me and respect me?