I would just ignore that guy.Suggestions:
Does South Africa have particularly close ties with Ethiopia?
I thought it was super obvious Ethiopia will be a pro-China element in BRICS. It's practically China's East African BRI poster child (despite their war). China built the African Union HQ in Ethiopia and even tried to mediate the Tigray war at some point.
China definitely needs to continue strengthening its relationship with Indonesia. It is one of the countries where its approval rating is really high. So I don't think you really need to worry about it. Aside from Philippines, the rest of ASEAN is becoming closer to China, including Vietnam.
What will get China & Indonesia + rest of ASEAN continually closer is more local currency trading (which Indonesia also pushes for) and tech sharing and more investment. All things China would be foolish to not continue on a mass scale.
As for the latter part, I'm sure China also wanted Ethiopia to get in, but always good for Ethiopia to have another major backer.