Wow!!! First of all be glad that he is not doing real drugs. The only way to convince your brother to stop smoking weed, is that if and when he goes to apply for a job, most places piss test and he will end up failing if he does not quit. Dont let him borrow money, dont buy him food, dont buy him anything. Its like cigarette smokers who are always asking someone for a smoke, buy your own damn smoke. Secondly, why should he stop smoking weed, does he have a reason to. Ask yourself how is it directly affecting you. If your just mad cause thats what he does with his money, then you have no real argument. If hes begging for money then its a problem. Last, never involve the police for you family affairs, they will ruin your life as well. you will end up being a torn family and will never get any respect from him no matter how much you disagree with his habits. Be happy hes not doing cocaine, heroin, crack, meth, crank, or some drug that people steal from theyre family members for just for a hit. Weed is not addicting,cigarettes is harder to quit then weed.