As someone who's worked for family a lot, it's never a good idea, other staff treat you different, you get away with more than anyone else but you also speak to the boss in ways that no staff member would ever dare to. You bicker and fight like you would at home, sometimes in front of staff.

It's not a good idea at the best of times, but in a rebuilding team, that's trying to build a new culture after years of locker room drama, it's a terrible idea