This is already impacting futurology.today - one of the Mods is British, and because of this law doesn’t feel comfortable continuing. As they have back-end expertise with hosting, if they go, we may have to shut down the whole site.

Its good news that they are merely a mod and not an admin / op, then! That’s why documenting and transfer of knowledge is important! If they don’t feel capable of dealing with a stupid law, they should make themselves unnecessary to your community ASAP! Have them prepare to step down from the role by documenting everything that a replacement needs to be able to do, then as soon as another mod can test that the documentation works, derole them if that’s what they want.