Lyman,
Are you a pilot of any sort, meaning have you solo'd any airplane...
I think that the answer is no from what you've written. My observations here have nothing at all to do with any given airlines "SOP". Things like unreliable airspeed can happen on any type of plane. Learning how to deal with these types of issues is a fundamental aspect of learning to fly. From what I can recall no mention of any checklist or procedural conversation has been highlighted.
The immediate response to unreliable air speed is to fly pitch and power and then once the plane is stable the PM can begin to sort out the details. The PM knew the PF was not responding correctly but i'm unaware of him initiating a formal scan related dialog. Meaning at no point did he read off pitch and power to the PF...which may very well been all that was needed to put the PF's head back in the game.
Aircraft law is derived from admiralty law. On any plane or ship there is always a chain of command. with the captain off the flight deck the PM was the senior staff member on the flight deck and unless otherwise specifically stated command authority was delegated by the captain he legally was in command of the airplane until the captains return.
By the time the captain returned it is entirely possible that the airframe was no longer recoverable. However from what dialog has been released and conversations here the Captains actions were entirely incorrect. He was unable to clearly see the PF's inputs or instruments. By relieving the PF and having the PM assume control during the brief transition he would have accomplished two things. The PM seems much more capable and coherent so he would have gotten a much better situation update in the 15 or seconds it would take to strap in and do a scan. He could then assume control and have both the best experience level and most accurate information.
It is inconceivable to me that the airplane crashed without the captain at the controls.
My comments needed no defense simply because they are so self evident and fundamental. Any pilot candidate would be fully expected to know that you fly pitch and power under those initial circumstances as well as understanding that the 1st step in unusual attitude recovery is to unload the air frame. It was fundamentally incorrect for the PF to apply any back stick pressure beyond what was required to level the airplane. The moment he began to climb the PM knew it was a mistake and failed to exercise his legal obligation to take command of the aircraft until the captains return...period end of story.