Reading almost any of the twenty-four numbered sections (with their three voices) will tell you the answer to your question. The key to this answer, of course, is the final voice. This final voice is always personal and, most of the time, about Momaday's grandmother: Aho.
Yes, Aho did once acquire "powerful medicine from a mole," but most importantly, she was Momaday's own grandmother. The reason why this is important is that Aho experienced many of the important events in the Kiowa tribe during its heyday. Most specifically, Aho experienced the Sun Dance. In 1887, Aho experienced the last complete Sun Dance where all of the religious rituals were completed. Likewise in 1890, Aho experienced the final Sun Dance that was left incomplete. This Sun Dance was left incomplete because the soldiers from Fort Sill arrived and dispersed the Kiowa tribe forever. This bit of history is recorded in the part of the novel entitled "The Closing In."