Abused by son

Dear Sir/Madam, My younger brother who is about 35 yes old was addicted drugs(ganjai) and chain drinker he is out of family ethics due to this I was separated and married a girl, resides i n Hyd in other place, he uses bad language on my mother face now he beats her up to bleeding and tried to kill her by pushing at 3/rd floor, she has an only income through rents from property which was gifted by her brother, (for thrice she complained in local police station they kept him hardly 3/days everytime, may be there is no FIR, It has been 6 years that our patience becomes our weakness now I have decided to make him murder , may I know the punishment and tenure of imprisonment, becoz I have 5 months baby girl where my wife is not so literate to get a job and take care of her. To tell about my father he is just father for certificates, he also drinks a lot and sometimes when my mother is not at home they both sits this was came to know by our neighborhood. To obtain advice I was shamed to urge, I want to be my mother safe. Kindly advise me how can we get rid of him., Thanks for your valueble time. Surender.