>>47528500>>47528627 (me)Wait, I gave it some more thought.
Encourage him to play some games off-screen with the rest of the branch, or do some discord watchalongs together so he can try and find a click with the rest of the branch.
Place the reality in front of him that sometimes things that are good as a gamer, aren't good as a streamer.
Find ways to showcase his talents. Do some short voice acting skits on schedule maybe. Or have him read books, mangas or VNs he likes where he can do the characters.
1 meta-whore game on a weekly or at least a regular basis. Whether it's MC, Duolingo, some Chilla's kusoge or whatever else is popular right now. Vampire Survivors got some low 3 views to 4 view on Twitch when it was hot. Some people will stick.
All out of ideas if that doesn't work though.