Hello @saubury and welcome to the community,
Definitely not a “silly” question if it’s one you had and couldn’t end up finding.
This seems like it may be similar to another recent post by another user here asking about multiple Family Organizations and vaults.
Short answer, each premium plan such as the Families plan is valid for the Organization that the subscription was created for, with the family plan you will have an organization with a shared Organization vault to share logins with your family.
Any members of a premium Organization will also have those premium benefits appy to their own personal individual vault items as well.
Hope this helps to answer your question, and feel free to check back in if you have any other usability questions.