How to get the commander to use binoculars?
Remember to allow the commander to move the cupola gun, he must be in the right fire mode AND using the machine gun reticle.(with rangefinder markings), (green mans head icon highlighted below)
If the cupola gun, is not pointed in the same direction as the main gun, there is no option to unbutton the top.
When the cupola gun is aligned with the main gun the unbutton option is available and now can use binoculars.
Wallaaa!