It it like he can see us but we can’t see him?
Opposite way around. We can see him but he can't see us.
The reason you can't see him is because you're on Lemmy which will only display microblog posts if they're (1) a reply to a Lemmy post, (2) made from kbin/mbin, or (3) replied to by someone from kbin/mbin (not entirely sure about this one).
That's why I use Copilot.
Asked it for the official documentation, got a link to the /current/ documentation's chapter on operators. Then asked for the heading about the IN operator and it gave me all four of the numbers. No need to wade through outdated or irrelevant results.