As non-flying pilots, their duty is to notice attitude, not the controls that produced it. "Yoke,Yoke"....... That makes them an instructor, and is not in the quiver of a highly charged cockpit.
Respectfully, no.
In multiplace aircraft, when the other guy isn't doing great at flying, you do indeed resort to "instructor" type techniques and behaviors in order to get him back into the ball game. In some cases, you have to take the controls, but more often it is simpler to talk him back into the game.
"Lower your nose ...
Roll left ...
Ball's out to right, step on it ...
Add power...
We are sinking -- POWER POWER POWER! ...
The Gear's UP! Wave OFF! (Go Around!)"
All of these are solid actions / calls that in some situations must be initiatied by a good co-pilot (PNF) that are also "instructor" actions/calls.
The two roles overlap; they are not mutually exclusive.