Aggresive violent depressed drugs intake

My brother is into his last year of college.I have found 2 months back he is smoking ganja weeds.from last few years his behaviour has changed a lot.he hardly talks to anyone in family n whenever he talks derz always a conflict due to difference in opinion.from last 8-9 years we had lot of financial problems at home because of which there has been lot of conflict in daily neccesaties n all.he was very emotional n loving person before but now from 3-4 yrs he just keep on playing world of tanks on his mobile laptop TV n hardly talk wt anyone at home.he talks very nicely with his friends n daily meet dem who are also indulged in all wrong doings but dey have high family backgrounds.me n my family tried to motivate encourage him alot bt he is not ready to hear a word from us n very arrogant rude behaviour We tried to ask him alot wat is his problem.he is not telling us a single word.yday tears came in his eyes wen v wre talking to him but he kps complaning abt everything his carreer family