

It used to be BRIC (Brazil, India, China, Russia) or BRICS (same + South Africa). In the article, it has been extended again to other nations, therefore “so-called” because its membership is not the same anymore. Also, the membership seems very informal, it’s just a bunch of countries maintaining ties and having discussions, not a real group of countries, with its own set of rules and institutions.
You have to define ‘we’ and you also have to define ‘WW3’.
Possible scenarios:
USA decides to get actively involved in Ukraine’s conflict. Yes, that could spell WW3. Low probability, though, since Trump does not care about Ukraine.
Russia decides to attack Western Europe. Probably only a regional conflict, since Trump would probably pull out of NATO. This is the scenario a lot of European nations are gaming today.
China attacks Taiwan and/or North Korea attacks South Korea. Probably a regional conflict, but with a high probability of escalation. Trump would drop both South Korea and Taiwan at the drop of a hat.
Iran attacks Israel, probably through proxy. Regional conflict. This is already going on, so low risk of escalation.