Question about a self-proclaimed stutterer who has "cured himself"

Question about a self-proclaimed stutterer who has "cured himself" I typed stutter in Youtube and fluency and went down the rabbit hole. I recently came across a guy who calls himself Craig Coffee. I saw some seconds of his videos and I am a bit conflicted. On one hand I believe in will power, on the other hand I am not sure if this guy is legit or is he on to something. Please assist.