No one needs Plex pass. I don't even recall what it does. You just send an invitation to their email. It will try to get them to subscribe, but they don't need to. They just need to accept from you and setup a plain account. Maybe even just login from a Google account.

You may need to walk them through setup/installation on whatever device they use, because Plex tries to put a bunch of things that aren't your content on the home screen.

Strangely, Plex (remotely) performs differently depending on the device. I've never had any issue with a computer or phone (you do have to make a one time $5 payment for the phone app). My horribly slow TV runs Plex surprisingly well. It runs like garbage on my PS4, and sometimes struggles on my Xbox series X.

If the streaming runs choppy for remote users, there are some settings you can adjust. But that's another story.