Need Assistance

So I recently updated my dad’s iPhone 5s to ios 12.4.5

but unfortunately the incoming call numbers are too big for the screen and they keep moving without giving him a chance to read them. I was hoping for a way to resize the numbers so that it would fit in the screen without moving. Is it possible?

Sorry I didn’t pay attention to the numbers. It’s ios 12.4.5

Thank you for your time. I just did.

Tried it plenty of times. Unfortunately it doesn’t affect the incoming calls.