People still end up finding out, over time - if not what he's lived through, then in living through their own experiences. Whatever caused those worlds to collide would either destroy them, or find an equilibrium once everything hit its boiling point.

I have seen that it's possible for ghouls and humans to coexist, to the point of being in love.

"Can ghouls and humans have children?" She asks while staring out at sea, watching the scant moonlight dance across the surface of the dimpled, darkened sea.