In flight is impossible to see what the other sidestick is doing.
You can only see what the control surfaces are doing if you have the Flight Controls page.
And one more hint, in the Gulf Air crash in Bahrein, do you think that the F/O was aware of the inputs of the Captain?
Was the F/O aware that was really the Captain who was pushing the plane downwards, or he was thinking that the captain was trying to recover from a pitch down?
In other plane is easy, if the Yoke goes foward and the nose down, the other pilot is driving it to the ground.
If the yoke goes aft and the nose down, the other guy is trying to recover.
It is easy right.
In the Airbus aint so easy, everything is more complicated, except the cruise, of course.