Mubarak showed goodwill towards Ezra Zephyr because he genuinely hoped that someone amazing would arise from their group.
However, this mindset was clearly not shared by all the other disciples. James Endoro for instance disliked how much attention Elder Lo was showing Ezra Zephyr. Although Pele appeared to be the mastermind, James was likely sparing no effort to support the former.
Mubarak also knew that his junior brother James did not truly acknowledge him as the first disciple because the latter's talent was greater than his own. Although James had joined later, he was fast catching up with his senior brother. Hence, he was usually not too respectful either when they met.
"Junior brother James, junior brother Ezra has great potential, and it can be said to be our fortune that he has come to Alchemic Rune Peak and Elder Lo's faction. The cultivation resources we give him now will surely be returned manyfold in the future." Said Mubarak.