Hello Norwegian_Macfan68,
Thank you for using Apple Support Communities!
We understand from your post that you would like to use Shortcuts to create a one tap button that will clear all the tabs in Safari on your mother's iPad. This article has information about using the Shortcuts app, so you can determine if the Shortcut you want to create can actually be created or not:
Shortcuts User Guide - Apple Support
Another option, is to clear the history and cookies in Settings which will close all the tabs. This article will provide you with steps on how to clear the history and cookies which you may find helpful:
Clear the history and cookies from Safari on your iPhone, iPad, or iPod touch - Apple Support
Best Regards.