I also have questions re how the video squares with a Stabilator failure, assuming it went full down in cruise flight for example, and how the aircraft would react.
My thought is the video shows a nose down pitch attitude but with the high rate of descent in that nose down attitude it seems to me the nose would have tucked more with the increasing airspeed and gone inverted.
Not saying that is my choice of causes....just trying to look at the video and question what we are seeing as we try to come up with possible causes.
What model UH-60 was it?
What kind of SAS/AP/FD gear did it have if any?
What was the nature of the training being conducted?
Were these Full Time Guard Pilots or Part Timers?
The formal investigation will offer up a great deal of information when it is all said and done.