If Kotonoha didn't find out that Tongmo was a ghost, Tongmo got married and gave birth to Inosuke, a half-ghost. Inosuke didn't join the Demon Slayer Corps, didn't learn breathing techniques, didn't know there were ghosts, studied medicine, Tongmo died, basically recalled killing, and was a good father and good husband.
Purpose: Tong Mo becomes a good husband and father