Ok lets use a bit of problem solving skills ourselves.... what if he is led to a place or forced to come in contact with something that makes him lose his memories or become unconscious or even comatose, maybe that would produce enough hesitation to kill him. I don't remember him saying anything about killing things in his sleep. Or maybe an innocent person is made to trip and fumble into him in a way that uses ordinary objects to cause his death? Not unlike a dad who slip on a toy car down the stairs. Maybe the confusion of falling would hamper his ability to kill the lethal object?
Well we have seen him kill powers haven't we? Could he kill gravity?
About his sleep, wouldn't he be always aware of the cloud of death looming over himself? Maybe that would be enough to wake him up?
Also if you do manage him lose of his memories or make him comatose, wouldn't it ultimately be done with an intent to harm him? Would that also show up in his cloud of death? Maybe you could leave him alone with a memory loss and don't take this any further, ever. That might not register.
But at that point have you really accomplished anything? If by coincidence he does end up in the same scenario then are you gonna just keep memory wiping him forever?
And also, what if the Yogiri after a memory wipe is a different Yogiri? Maybe one with a slightly more bloodlust? Would you want to risk that?