Prisoners on a Strange World

[Infinite-flow, no female lead, fictional setting, sci-fi apocalypse, intelligent protagonist] Xu Muchi is diagnosed with a terminal illness. He plans to forgo treatment and enjoy what little time he has left, but then he suddenly realizes that the world he has lived in for over twenty years is strange in every way...

The supermarket downstairs is fake, his wife is fake, even the entire world is fake...

Xu Muchi panics. Clinging to a faint glimmer of hope, he wanders all over the city, but everywhere he looks, he sees nothing but despair.

Yet just as Xu Muchi is about to lose all hope, it appears before him once more...