Why is Gordon's character in this novel? What is his significant role?

Gordon is a First Nations character who adapts to the white world in the novel. At first, Gordon is supposed to marry Keetah, as this union has been arranged by Keetah's grandmother. However, early in the book, Jim says to the vicar, Mark Brian, "Gordon is Che-kwa-la, which means fast-moving water. . . and Keetah is the pool" (page 48). Jim notes that Gordon has a character that will continue to move and change, while Keetah prefers stillness and staying in the same place.
Gordon attends the government school in Alert Bay, and he has already lost his father to the sea in the Queen Charlotte Straits. His mother dies while giving birth to her sixth child at age 46. As she is dying, she implores the vicar, Mark Brian, "Help Gordon get an education" (page 82).
When Gordon attends his mother's funeral, he confides in Mark that he will now have to leave school. However, Mark has other plans. He sends the older children in Gordon's family to the residential school with Gordon while the younger ones are cared for in the village. As Gordon leaves for the white man's school, the author writes of Gordon, "he was leaving his boyhood behind and would not find it again." 
Gordon feels at home in the white world. When he returns home, he is wearing a "city suit," and his face is characterized by "discipline that marked the size of his battle" (page 121). In other words, it is evident by Gordon's face that he will fight to assimilate into the white world, even if this quest is very difficult. Keetah joins Gordon in the white man's world but returns home again. She knows that Gordon would prefer to marry a white woman and that she is "too Indian for Gordon" (page 138). Gordon's role in the novel is to become educated and push for assimilation into the white world, while Keetah stays in the village and marries Jim.