A question about hitogami in oldeus timeline.

So I know hitogami is a liar but when he spoke to rudeus after he read the diary and rudy asked him why he had to kill all his wives and close friends. Hitogami said maybe he did it for insurance but wouldn't he already know what he told oldeus throughout his life? with his future sight and all, knowing what he will tell rudy from the moment he opened that basement door. but he was acting like how tf would i know what i told him. And now that I'm writing this wouldn't he also see that rudy will time travel or to him he thought it was impossible and he will just assume rudy killed himself.

Or maybe I'm going down a useless rabbit hole lol