Even if you uninstall the EP it will show as owned in Origin and in the game itself.
You can disable it so she won't have the content or try deleting it and turn off automatic updates but I guess she would still know ?
I can give you instructions how to do that if you wanna go down that road (both ways are done at your own risk).
I guess another option would be to talk to support if they have a way to handle this.
Here's instructions for disabling: https://sims4.crinrict.com/en/2017/03/disable-single-packs/
To delete the EP, you need to turn off automatic updates.
Then go to this folder: programs(x86)\Origin_Games\thesims4 (path may vary depending on your installation) and delete the folder EP04. There's also a folder EP04 in the folder Delta. Also delete that.
Origin is notorious for trying to reinstall the EP nevertheless though, especially if there are patches. You will need to manually patch the game on the next patch (it will tell you there's a patch so just click on update on Origin). If it starts redownloading the EP, just cancel the download.
