I am just trying to find a word that describes a friend who means as much to me as my family does. I have searched google but have not found such a word.
Soulmate, perhaps - a person who shares a deep understanding or bond with another; esp. one ideally suited to another as a lover or spouse.
1822 S. T. Coleridge Let. to Young Lady in Lett., Conversat., & Recoll. (1836) II. 89 You must have a Soul-mate as well as a House or a Yoke-mate.
1847 Howitt's Jrnl. 6 Mar. 128/2 She could be neither soul-mate nor help-mate to such a man.
2006 Psychologies (U.K. ed.) July 14/3 We all hope to make a few deep and lasting friendships, but... we can have other friends who are fun, kind or useful rather than being soulmates.