Abusive brother. He causes disturbance in family. What can be done?

Hello, This is regarding my family issues. My father is businessman and I have 2 brothers no sister. we all three are married and having kids. I am working in Delhi since 2005 and my youngest brother takes care of shop and help my father to run family. But from some times my middle brother is disturbing badly and threatening all the family members and demanding huge amount every time. If not given he breaks household commodities. My shop remains close many days and my mother and father goes in depression every time. we are just hopeless please help. Thanks in Advance.