The Hawaiian concept 'ohana: emphasizes that families are bound together and members must cooperate and remember one another. (Wikipedia)
According to www.edu.pe.ca/southernkings/familydefinition.htm:
Families are who you love. Our families all “look” different and it's always been so. A family caregiving unit might consist of a couple; a mother, father and children; a single parent and child; grandparent and grandchildren; a sibling group; a circle of friends; or however that family defines itself.
Family is who is there for you. It doesn't have to be those related by blood. It is my experience that those are the least reliable. That isn't so for everyone, but it is for me. My family is my husband, my children, my in-laws, and a few select friends. They are there and have been there. They do not feign understanding and acceptance. I respect that.