Legal separation from brother

I am an central government employee, staying in mumbai with my family. My parents died in 2009. I have one brother who is 7 years older than me and staying in kolkata. He does not earn and is financially dependent on me. I have been financing him since 2009. In 2011 he got married and I was informed only after his marriage. Initially though i did not pay him, he pestered me for money and also out of compassion i stared sending him moneyagain. I send him Rs5000-6000 per month which i find is reasonable for kolkata as he is staying in the our ancestral flat only. The problem is he gets into fight with each and every person in the building where our other relatives also stays. They starts calling me telling me about his actions. He also disturbs me for more and more money from time to time which I am unable to give. I want a legal separation from my brother. I want a legal statement that I am in no way responsible for his actions. If tomorrow he is doing something to someone then I am not liable for it. Basically I want legal separation. He mixes up with antisocial people. I want to separate myself from such elements. He has also married a lady from bangladesh and they get into fight often. I have only seen that person during a family marriage and have never interacted with her. People whom he is disturbing are telling that they are not able to take any action against him as I may contest their action. I will never contest as I am myself very much fed up with his behavior. Though he has no medical report of madness but he behaves like mad and I am surely unable to hanlde this. I will send the copy of my legal separation to all relatives so that they may take any action against him in future. Kindly advice me regarding this. I want a legal stampped document for this.