Good on him for sticking with his hypothesis far enough to research it thoroughly, write it up, and publish it in a peer-reviewed journal, and now that he has done that work, he might start to turn heads in a Ph.D program. But otherwise, rejection from Ph.D programs after applying with an idea and no credentials is a bit like saying "Based on my new theory of radiation-proof ultra-thin materials, I applied to NASA, ESA, and JAXA for a head researcher position but was unceremoniously rejected." Of course you were, mate. You have no demonstrable history in the field. They want to see at least a working spacesuit prototype first.