Hi KFGatri
welcome to this Apple (user-to-user) Community!
Re: "Screen zoom focus to new items automatically? Can this be done?"
We are all Apple users, like yourself, in the community. A vision or accessibility professional may be able to suggest the best options for your cousin. (eg: There may be specially designed third-party apps that are tailored to suit your cousin's vision requirements)
Also, for Apple's software: We don't have much info. to go on:
ie: Wondering what hardware (Mac, iPad, iPhone ) model, and which software macOS, iPadOS, iOS version your cousin uses..(NB: Is often wise to keep a device updated to the newest compatible OS version.)
Apple has various accessibility software solutions:
Eg: Accessibility features for vision on iPhone - Apple Support
says:
With built-in accessibility features for vision on iPhone, you can make it easier to see what’s on the screen, or you can hear what’s on the screen spoken out loud. You can even use your iPhone as a magnifying glass, and hold it up to get descriptions of what’s around you if you can’t see it.
To explore accessibility features for vision, go to Settings
> Accessibility. Vision features are at the top.
Also says:

Zoom in
Enlarge what you’re viewing—the entire screen or one part of it.
Zoom in on the iPhone screen

Make text bigger and bolder
Adjust the reading size for text across iPhone apps and system features.
Make text easier to read

Enlarge text as you type
Display a separate window with a larger version of the text that you’re typing.
Use Hover Typing
Note: There's much more iPhone info, in that linked article at the top
_______
For Mac: There are also specialised articles like:
Zoom in on webpages in Safari on Mac - Apple Support
_________________________________________________________
An option: It is possible to:
Join a community of Apple users who are blind or have low vision.
Pasting two links here below, if you are interested:
Community: https://www.applevis.com/
Forum: https://www.applevis.com/forum
All the best :-)