‘Multi-Account Containers’: https://support.mozilla.org/en-US/kb/containers
With it, you can open tabs in different ‘containers’, which have their own set of cookies, etc… So, for example, you can be logged into two accounts for the same website, just in different containers, or keep all your shopping accounts in one container (and set those sites to always open in that container) to reduce tracking and targeting.
He has a neurological condition, spasmodic dysphonia (https://en.wikipedia.org/wiki/Spasmodic_dysphonia)