My fiance` lost his job and wants to keep it a secret?

Maybe it will never by your families business that he's lost his job. Let HIM be the one to call the shots about what is told and what isn't. If you are loyal to him, then allow him this dignity. There is nothing wrong with keeping such a secret from family. We don't have to tell everything we know. Some people are more private than others and it's quite possible he just doesn't like the world knowing his business.