The story itself is decent and competently written, see how it keeps track of the analogies and phrases by different characters (wrapping it all up in the end, tying the "no-man's minute" or how the ex wife told him he was always somewhere else than here). If an un-assisted LLM did this, I'd be surprised. I think there may have been LLM-assistance to polish it up (maybe) but there are some human ideas in here. I'd be interested in the author clarifying this.

The sad thing is that an LLM can't really polish a story. "Polishing" is the most important stylistic work. Even a rough hard to read story is superior to one polished by an LLM.

I think the theory posed above (that the original story is in Russian) makes a lot of sense.