First - wow! What a swing!

The "instructor" seems to be telling the student to not move his head.

Greg, as a teaching professional, would you mind explaining what the "mis-instruction" here is? Is this just the most minor problem for this guy? Or is the teacher off-base? As someone who only concentrates on my own issues, it is interesting to hear how and why another is destroying the golf swing, and what your advice for him would be.

P.S. I'm not the guy in the video :-)