Symbolism, Imagery, Allegory
The idea of Western medicine is also implicit in this story. Western medicine basically refers to medical practices developed primarily in Europe and (post-colonization) North America. If you're picturing a guy in a white lab coat with a stethoscope around his neck jotting down a prescription in barely-legible doctor handwriting, then you're on the right track. Western medicine is often treated as superior to its various counterparts, though these other medical traditions have in many cases been around a good deal longer and often focus their attention on different components of the experience of illness. If you're thinking that Western medicine seems like a racially and culturally loaded term, you are absolutely right. It's an us-versus-them model and, as an idea, it's been circulating for the past few centuries.
Because Nick's father is a white doctor being called into an Indian camp, there is a nod toward the idea that the "Indian" medicine isn't able to resolve the Indian woman's condition, and a wiser and more authoritative figure needs to be brought in. So Nick's dad is in an even more privileged position because of this idea of Western medicine—but again, because Western medicine in the story is so emotionally distant and rational, it has no idea how to react in the face of something as ambiguous and multifaceted as suicide.