How to deal with a vaccinated family member

That’s a dangerous assumption to make. We don’t know if there are now or will be mutations that will get around the immunity given by some of the vaccines.

The goal should be for everyone to cooperate and put up with inconveniences as much as possible until we can reliably get seasonal vaccines throughout the year. Once we can achieve some degree of herd immunity (may be regional herd immunity more than widespread), then we can gradually go back to normal.