Sorry, that won't work either. The crust has lots of naturally occurring radioactive material in it. The deeper you go, the more stuff you find. A lot of the interior of the planet is kept warm by radioactive decay. And this is the ionizing stuff, not just EM. Plus, don't forget things like cosmic rays and neutrinos that can penetrate a great deal of solid matter. He also better not have ANY light sources whatsoever in this house. If he has so much as a light bulb then what he is claiming is false. Visible light is even higher frequency than his horrible 2.6 GHz wifi.