Use ipad for low vision video magnifier

I have an ipad pro. I want to use it as a low vision magnifier to read books. However, i need a camera to mount looking down at the book while dad had the ipad up to look at.

1) is there a way to link his iphone's camera (use that as the downlooking camera) to his ipad screen?

2) does anyone have a good way to do this?