Hold on to your butts, comrades. We're about to get a preview of 2050. I just checked the live data, and the area off the coast of South America that is the index water for ENSO is 9° F above average in places. This is going to be a wild year.
And if a massive climate disaster event occurs, do you think that'll be enough to convince them
For a lot of people, I do. I think many people like this are ultimately buried in their cultural context, and never had an event breaking them out of that mould / making them question what are for them basic assumptions about reality.
I think the vast majority of people are good and would care; it takes constant reinforcement to make them accept (and for many, barely, despite the image they may project) their constant participation in an absurd, evil system and to make them actively link their self-worth to it.
Also, at the end of the day, there are more and more people barely surviving and there are less and less people like your brother as time goes on; eventually we reach a critical threshold. And at that threshold there are a lot more of the former than the latter willing to fight.