Family is what you make of it. It can be anything you like. It is said that you cannot choose your family but you can choose your friends. I am not sure that is entirely true. I suspect that there are instances where it is possible to choose your family. It depends who you are and where you choose to call home.
Every single person on this planet has at one time or another been a part of a family. Whether that family proved to be dysfunctional or not is immaterial. Whether the dynamics were skewed, or the values lacking, a family at base-level inception wants the best for all its members and this means it will pass on its greatest strengths in addition to its weaknesses. It is what a person makes of weakness that determines their future.
Family is a social concept. It works. It is not something that is determined by a name, or a label. It is a feeling. An understanding. Family members get each other. That is how you know you are family. A family celebrates its members. It is not intolerant of them, nor does it try to repress its lessons, if it is wise. What are lessons for, unless to learn from?