Nobody's truly lost, I've seen people make the jump from proud neo-nazi to leftist so don't give up on your brother just cause he thinks capitalism is good. Hell, I've found "libertarians" to be the easiest to convert. Ask him to explain why he thinks X or Y and then highlight the flaws in his thinking instead of telling him he's wrong right off the bat. Show him videos of people like Shaun debunking some of the channels he might watch.