The problem is coming up with an agreement specially with weasel regimes like the Chinese who want to force Yuan on everyone replacing the dollar and nobody wants that 
It is impossible to predict what they'd do in the end.
It is impossible to predict what they'd do in the end.
I don't think any BRICS member would want to be linked financially to each other with one currency. These countries are all very authoritarian in their own ways and I don't think they trust each other that much
Why would Brazil want to be linked financially to say, Iran or Russia in case of sanctions or wars or something that has nothing to do with them? No thank you.