Trump is oblivious to the fact that BRICS is now a bigger economy than the G7. The US is no longer an essential part of the global economy.
Increasing trade outside of the dollar is the only way countries can protect themselves from economic coercion by the US. In particular, China can obviously see that the US will go after them the same way they did with Russia. So, it would be suicide to agree to tie their global trade to the dollar.
Meanwhile, China also happens to be a bigger trade partner than the US for most of the world. So if it comes to choosing between the US and China, it's not really much of a choice. Especially given that China exports things people actually need, while the US barely has any manufacturing industry left accounting for less than 15% of the overall economy. The US is a big market, but it's not essential the way China is.
Completely agree with what you have said, I guess my fear is that the compradors will influence economic policy in these countries to a degree that will undermine the dedollarization initiative at least in the short term. I'm totally with you in thinking that long term its against the material interests of BRICS nations to do this but I guess I have been taken off guard by some recent developments in this area and it has made me doubtful. Perhaps also the bad news this week in Syria and such has just put in a pessimistic mood.
Luckily, American policy puts an immense strain on dollar hegemony. For example, Russian compradors didn't want to antagonize the West, but were forced into it, when the alternative was slowly losing their wealth and status.