Unrelated one- https://www.neowin.net/amp/ublock-origin-lite-maker-ends-firefox-store-support-slams-mozilla-for-hostile-reviews/
The two in I use are for twitter-
https://addons.mozilla.org/en-US/firefox/addon/blue-blocker/ - Blocked in Firefox since after 0.3.5, which makes it useless since 0.3.5 was prior to the forced change to x, iirc.
https://github.com/dimdenGD/OldTwitter - Removed from Firefox entirely. Still available on Chrome.
Combined those two make the site look like old twitter, lets me save videos with a right click, and blocks twitter blue users automatically.
reset his account password clearly. make it his problem.