How can I make dialer fill screen for visually impaired?

Huawei Nova Plus,Emui 5.0, Android 7.0

My visually impaired father uses voice activation, but sometimes he's somewhere he'd rather not make noise. How can I set up his call dialer pad so it takes up the whole screen? Right now it is only filling the bottom 2/3 of the screen, and has call history on the top 1/3. It would be very helpful if the dial screen took up the entire screen. If there were a way to make the actual numbers on the buttons larger, that would be a bonus. Thank you very much!