Sorry if my English is a little bad.

Me and my husband have known each other many years. We met when we were children. We were arranged for marriage. I was nervous but he turned into the most amazing husband. I am currently pregnant with his child. My sister has a son who is 13 and arranged to be married. The girl is living with them because both her parents passed away. My sister and her husband are not good parents. My nephew is spoiled and a rotten child. He treats everyone badly including his fiancè. He's only 13 and he has hit her and has said he can because she's going to be his wife. My sister and her husband let him. We don't really see them. We saw them recently when we saw my family. My mom, sister, female cousins, and nephew's fiancè all made dinner. My nephew told her to practice being a wife and bring him food and she did and he slap the plate out of her hand. My sister told her to clean it. She does and nephew kicked her in the side. My husband asked him if he knows what it means to be a husband and she is going to be his wife is 5 years so he has to protect his wife. My nephew told him she's her wife and he can do what he wants. He told my sister and her husband they should not be teaching my nephew to treat his future wife this way and they told him to mind his own and they are the parents. Nephew stuck his tongue out and my husband said "If you want to keep you I suggest you treat her better." My nephew said again he can do what he wants. She's going to be his wife and he will do what he wants and when they're married they will have intercourse when he wants. Whether she wants to or not because she his wife. My husband slapped him across the face. My nephew said he can't do that and my husband says "I just did." My sister and her husband got furious and we were kicked out. My husband will not apologize as he is not sorry. I know my nephew can be rotten but he has really upset my family. I don't know what to do.

Edit: sorry for poor English. He marries in 5 years when he is 18.

Edit: I want to say my sister does not get treated this way. They spoil nephew and believe he does no wrong which is why he's turned out rotten. My sister does not like this little girl because she's feeling she's taking her son away. My sister can be very abusive person towards others people. Her husband is lazy and doesn't care to parent so let's nephew have whatever he wants