"Demon voices" might be nothing more than very effective subliminals.
I use an affirmation program that runs a computer voice in the background. I cannot hear it consciously. I use this cheap little subliminal program for my work.
What if these "demon voices" he heard were instructions given subliminally via his media devices? His phone, his computer, etc.
The sudden urges people get? Is this some kind of satellite-cell/internet messages pulsed to us when the clowns want to provoke an event?