The code contains provisions that prevent a member from improperly favouring any other person. In this case, the test is simply a little more rigorous than it would be for a defined family member.
I don't think that it's necessary to expand the definition of “family”. The code really refers to the family unit, or the nucleus, as we say in Latin.
However, the issue of friends bothers me a bit. You could favour a close friend in the same way that you would favour your son or your wife, and that wouldn't violate the code.