How does The River Between prove that change lies in the hands of humans rather than fate?

In The River Between, author Ngugi wa Thiong'o examines how colonialism affects the individual lives and communities of Kenya. In the novel, the protagonist, Waiyaki, attempts to bring a Westernized, Christian-based education to his community without also eradicating their traditional culture.
There is a prophecy among his people, the Kikuyu, that a man will bring salvation for his people. Waiyaki's father believes that Wayaki is the man the prophecy speaks of. However, there is intense internal conflict among the Kikuyu people about over allowing Westernization and Christianization into their homes and community.
Waiyaki ultimately does not succeed in bringing this Westernization to his people or in fulfilling the prophecy. Instead, the Kikuyu choose to resist this form of colonization. Through this, the novel supports the idea that individual and collective choice drove Wayaki's plan, rather than a fate that was supposed to support his plan.