Parents are getting tortured & thearthend

From past 5 years, my parents are being constantly tortured, pressurized and badly abused by my brother who is just seating ideal at home and not earning anything. But this time the level of torture has gone upto an extreme extent when he has threaten my mom to kill her with a knife if she does not sale property. He has even throw bottles to hit her & abuses her badly. The words are unbearable to hear. I have seen his anger and insanity to kill her. I have seen the fear in my dad & mom’s eyes. I have seen them weeping. My dad is so much helpless that he is unable to think & take any decision or do anything as he is in depression. My brother is treating my parents badly as servants and abusing them. I am scared to go to office and leave them alone at home as my brother will kill my mom. My parents have really tried hard to sale all 4 plots but there are no buyers. My dad has not taken any loan from anyone or he is not even under any debt. He just wants to get rid of this mental and emotional harassment and wants to sale the land and give money to my brother and let him go away forever so that they can leave peacefully. My dad is 60 years and mom is 58 years they are not working or we don’t any business or source of income to earn. My brother blames my parents for all his failures in the life & that’s why he wants to take revenge and take away all money which we get after selling all 4 plots of land & want to settle down in Bhavnagar or Baroda with a dance bar girl. He is very stubborn, that he will not get married to any girl belonging from a good Gujarati family, wont work here and wont stay in Mumbai at all also he is forcing my parents to transfer Mumbai flat at his name. Basically he wants my parents to be beggars in their old age. Awaiting your help.