I'll give Denny credit for one thing. He learned how to monetize his daughter's success. That's not to say they aren't good instructors, but he's making a killing at what he does.
Yeah, he did well.
I have no idea what the pay structure is for him. Does he get a cut of each lesson a "Tincher-certified Instructor (TM)" gives? Or just the initial "certification"?
He has plenty of free videos out there. I watch most. Some are showcasing a student so less informative, but many do show that he knows what he's talking about. Pretty scientific, and he's done a tone of research and consulted with doctors and scientists and such. Seems pretty legit to me, but I'll admit I'm biased.
I count 80 instructors under him.