I was so pleased that someone else has also asked AI to find Boily's story.
I remembered a book I wanted to read that I had scoured the internet for and it only took two queries for ChatGPT to find it. Its first suggestion was wrong, but sounds good.
The book I'm thinking of was The Afterlife of Walter Augustus by Hannah Lynn
Walter has been dead since the 1800s, lingering in the afterlife until the last person who remembers him passes away. Just as he's on the brink of moving on, a modern-day writer stumbles upon his name, anchoring him once more. This poignant tale explores the unintended consequences of remembrance and the longing for closure.
But it first suggested The Brief History of the Dead by Kevin Brockmeier. This novel presents a unique afterlife concept where the deceased reside in a city-like realm, remaining there as long as someone alive remembers them. Once the last person who remembers them passes away, they vanish from this intermediary world.
The narrative intertwines this metaphysical premise with the story of Laura Byrd, a woman isolated in Antarctica following a global pandemic. As the virus eradicates much of humanity, the population in the City diminishes correspondingly, since fewer people are left to remember the dead. The novel delves into themes of memory, connection, and the impermanence of existence.
While the specific plot point you mentioned—where a man's departure from the City is delayed due to a historian's rediscovery—doesn't occur in this book, the overarching theme of remembrance affecting the afterlife aligns closely with your description.