I don't know, but the points he makes in his videos are known to any competent language teacher, so they are hardly dazzling discoveries. The accent he teaches is common in England today, but some people would prefer a slightly more upmarket variety. Perhaps I am just a little old-fashioned, though.
I find his claims for the short amount of time it takes to become taken for a native speaker hard to believe. An American actor might manage it, but no speaker of a foreign language that I have ever known could do it that quickly.