Define "sane". The main problem is that unless the other person is themselves an experienced meditator (or maybe very good at rationality), they are pretty much useless and might easily make it worse.

By far, the most typical reactions to someone stuck in the Dark Night or going through a peak experience are alienation, attempting to engage their psychological waste[1] or treating it as a mental illness[2]. Neither helps, only more practice and calming down does.

Overall, I don't necessarily disagree with you, but actual help requires either personal experience or sanity that would reasonably pass LW standards, and those aren't all that common (or easy to identify when you're stuck). I had enough negative experiences in that regard that I have a personal "shut up and practice" policy.

[1] Meaning, trying to engage the content when you should be engaging the thought pattern. It's like the difference between psychoanalysis and CBT.

[2] I know several people who had an early peak experience, thought they were Jesus for a few days and who got institutionalized. They typically didn't mind (Jesus doesn't care about wards) and it never lasted long, but that's the kind of response you get from most professionals when weird shit happens.