Is blood really thicker than water? (ohsch fanfic)

Naomi Nakamora has been friends with Haruhi ever since she moved in with her aunt and uncle in their apartment after her father died. They meet shortly after she moved in and became great friends. So when Haruhi is accepted into Ouran Academy Naomi also enrolls on a scholarship so she can not only be with Haruhi, but also expand her knowledge for a bright future. After a meeting with the host club she becomes a maid to help Haruhi with her debt. She grows fond of the host club but when her mother comes back after leaving Naomi and her father when she was just a couple months old, she offers to be with her again and be a family. But every good thing comes with a price, she has to move to America and leave Haruhi and the host club behind. She is left with a day to figure out what to do.
Only one question remains;
Is blood really thicker than water?