The sole fact that it's open source should be enough to convince anyone, but assuming your family isn't familiar with the concept you'd have to explain it to them. It can turn into a big conversation pretty quickly. The way I've done it (with a close friend group) is with the help of a friend, a respected member of this group who happens to be a developer and militant, so we were two people telling everybody that we need to switch, one of which essentially considered an authority in the matter. If I were you I'd try to find that second person. In numbers, you need fewer arguments to convince people.