Doc's profession as an allegory for altruism
In some ways, Doc's main affliction is the heartbreaking trauma the his beloved underwent during the war. His profession as a medicine man can be viewed as an allegory about people who are willing to help others, and their subsequent revelation. What is that revelation? It's the clear vision of the evil of mankind. Doc is there to help, so he is allowed to see the true violence and terror of his fellow men, as a victim of that violence.
K as a symbol for the female victim
K comes to epitomize the violence against women that Doc discovered during WWII. In fact, his memories focus around this particular aspect of warfare, the raping and pilaging part, because his memories were so affected by his love for K. K isn't even a full name, which might be a reference to the fact that maybe these things really did happen and he's protecting someone's anonymity, but more likely, she doesn't have a full name because her function in the story is to represent the nameless victims of crimes against women. The story shows her as dehumanized, because that's how she was treated by her rapists. Doc's main character feature then, is that he saw her as a truly spectacular human, worthy of love.
The motif of troubled relationships with women
Here are three women with whom Doc has a tense, confusing relationship: K, Sunny, and Mary Burns. That's almost every important character in the story. What does this mean? It means that femininity is a motif in this story, and the subconscious implications are that Doc still hasn't rectified his relationship to women after watching his fellow men gang rape and murder a woman he had come to love.
The allegory of the book of Hosea
In the Biblical book of Hosea, there is a prophet, Hosea, who is called by God to take a prostitute for his wife. This juxtaposition between prostitution and marriage is a key function of this novel as well, except that instead of showing prostitution as a voluntary entity, it shows the more true reality of women taken from their lives against their will and forced into sex slavery by evil men. But the allegorical structure is still basically the plot of Hosea, which might be an intentional allusion or maybe it's just another example of archetypes. In either case, the effect on the narrative is that Doc continually has to overcome his emotional difficulties around women in order to be in community with them again.
Mary Burns as an allegory for the kind of influence that doesn't help
Mary Burns is like an awkward step-mom, trying to figure out where she fits in the development of Doc's adoptive daughter, and ultimately concluding that she should be more in control of Sunny's behavior and parenting. Ultimately, this drives a wedge between Doc and Sunny, showing Mary as an obstacle, not an asset. The implication is that Mary overstepped a boundary, and the allegorical effect of her inclusion in the story is that Doc might actually be doing the same thing too, but in a different way.
