Besides Russia, China, and Iran, I don't think any other nation in the BRICS Alliance will be able to stand any Western sanctions. Many of them are indebted to many Western-backed banks so it will be difficult for them to become financially free. They will have to be loyal to the West to avoid sanctions and deprivation from financial benefits like loans and grants. However other Western unions like NATO could not be said to totally uphold democratic principles because some smaller nations in this alliance have complained of high-handedness from other more powerful nations. But most of these BRICS nations are ruled by autocrats but it will have little effect if these nations are united. Until these nations set aside their national interests and focus on promoting the ideals of the alliance, they will continue to be a social club.
I believe that any country could actually survive in the long term even under western sanctions, as long as such country has the baking of the rest of the BRICS, specially China and India, which are among the most economically revelant members within the alliance, perhaps that was the reason Argentina wanted to join the BRICS, to further strengthen relationships with Pekin and try to get a breath from the huge debt they have had through so many years. I believe China and Russia would be willing to adquire a significant part of Argentina's debt and re-negotiate it.
Though, since the block still does not behave as an actually Union of countries and they have not been able to issue their common currency (which has been a subject of much speculation), I will agre with you when you say this is for now nothing but a social club for presidents and authocrats to hang out.