Help Lost Stock Camera Icon

[Guiliana]

Somehow, my husband lost (or deleted) the stock camera icon on his unrooted Nexus 5, Android 6.0.1.
I know it's supposed to be impossible, but the only place I can find it is in Settings, Apps. The only selectable option is Disable; Force Stop is greyed out. All I could do was clean the cache.
.
I'm stumped. If anyone has a solution, please let me know.
Thanks in advance!
Guiliana

 

[AZgl1500]

pull out the Apps Drawer, it is in there, do a Long Press and it will stick to the home page

on my phones, the Apps Drawer is a white circle with two rows of 3 horizontal dots.

I always make it a point to place the System Icon on the Far Right on the Command Bar.
and then I place the Apps Drawer icon next to it on the left of it.

My command bar has from left to right, Dialer:, Aqua mail:, Textra:, Apps Drawer:, System

that way, everything you need fast access to is at the bottom of every home page.