It seems like he was at the very least close to that. Since we only get his first-person account it's hard to say, but:
> They discussed philosophy, psychology, science and the universe...
> When they went to their daughter’s birthday party, she asked him not to talk about AI. While there, Biesma felt strangely disconnected. He couldn’t hold a conversation. “For some reason, I didn’t fit in any more,” he says.
> It’s hard for Biesma to describe what happened in the weeks after, as his recollections are so different from those of his family...
> he was hospitalised three times for what he describes as “full manic psychosis”.
You don't get hospitalized three times for mania without being pretty severely detached from reality.
> They discussed philosophy, psychology, science and the universe...
I mean, I've discussed all those things with an LLM, mostly because I'm able to interactively narrow in on the specific bits I don't understand, and I've found it to be great for that.
The rest ... yes, definitely psychosis.
On its own, yes, of course. But this is coming from a guy who was hospitalized three times for mania, so when someone with that history says "we were discussing the universe" I take it in a very particular way.
An important part of using an LLM is to verify it's output, because they are very prone to just make stuff up. If you focus on what you don't understand, how do you verify the output?