So, did the old man kill him? That's hard to believe. But if he didn't, what else would qualify his declaration that no one else knows he is dead better than him?
@firefish5000
Perhaps the old man is Leon's dad, and that'd be why his wife killed herself.
"I gave birth to the one that betrayed humanity, better atone for that with death"
It'd also explain why the old man so readily believes him, since it was pretty obvious the MC didn't recognize him.