It now appears that the US Navy Officer was on the bridge of the HI at time of collision, but he was there to learn, not to instruct.
What tasks he had been given at the time is unclear though:
It also appear that the Norwegian navy is a secretive as their US counterpart. They claim that ongoing enquiries prohibit them from telling anything. (Eqv. to claiming "5th Amendment??)
Actually the same apply in most civilian accidents, where Lawyers will put a gag order on everybody involved.