Earlier quoted context omitted.
This is an excellent answer. Not because it's probably true (it's as likely the asker's friend has as much to contribute from a different background as they have to learn for their new situation) but because they're likely to hear more of this from people who'd prefer to occupy an echo chamber, so it's probably best to get a certain thick skin up now.
It's really hard to parse your tone from your comment, but you seem to be implying that people who think like me are A) wrong and B) advocates of homogeneous, exclusive cultures at companies. I know about the studies showing that diversity is beneficial, and I've seen it anecdotally in my own career. But "culture differences" are not the same as having no idea what your coworkers are talking about (which OP mentioned…
>this is an excellent answer
I thought he was just adding to your answer that OP's friend is much likely to hear the same from his new colleagues who probably just want someone like them at the head. So he'd need a thick skin to survive