Yeah, no. He's just a dumbass. As much as I detest something, during such critical and important situation, I'd just kept silent until the time had come to talk about it. If he really is a "straightforward" guy, then he's just an arrogant and insufferable prick who intended to claim MC's achievement. He said it in his own words after all.
The author has failed to write a character that was supposed to be annoying but actually a good guy and has his own struggle because as I see it, he's just all talk but no action.