I've only watched 3-4 of Dan Gryder's aircraft crash analysis videos; therefore, I don't feel strongly one way or another about him and his videos. In this particular video, Dan is making some really specific assumptions (speculation) about the minutiae of a particular pilot's life, habits, pilot training and experience which I believe would require Dan to have been a close friend of the the pilot, and not just someone who recently became acquainted with the pilot as the result of performing a post crash investigation. Dan repeatedly stated that the pilot drove the airplane straight into the ground, first starting at 5:00 of the video: "I can tell you how this airplane hit. This airplane drove straight into the ground, and there was no stall in this airplane. There was no stall in this airplane." Well I think we all know that a low altitude stall frequently results in an airplane diving straight (or almost straight) into the ground, and that could also explain the airplane's almost vertical impact. If a low altitude stall is what occurred, it would not be a CFIT (Controlled Flight Into Terrain) as Dan claims.
Dan may be right, or Dan may be wrong on this one. I guess we'll all know eventually what happened here, other than a tragic loss of life. R.I.P.