Torture done on my maternal uncles son ...

My maternal unty is under mental treatment..but now she is fine..when my brother was born from that day till today she literally tortured him ..ow he is 3 years old and from waking un in the morning till night she ,for each and every act of him scold him ..for that he didn't even dare to laugh .she beats him all the time, he always stay just like a jailer . Apart from this unty have extramarital affair. Each and every day she abuse my uncle my grandparents and every one of my family without any reason ..My uncle says that she is mad..but apart from taking medicine of that ..she has never proof herself as mad ..ow she wants divorce.My family is scared about the future of my brother.My uncle knew everything about it.still he won't take any step..he will let his son stay like this. He had never try to protest against this...