How do you respond to Verghese’s idea that he didn’t want to interrupt Kalanithi’s remaining time by trying to establish a friendship? What might you do in a similar situation?

The issue here is priorities: recognition of another's priorities, putting your own priorities in relation to those of others, and making decisions appropriately. Given the literally life-and-death situation in which the men find themselves, situations in which readers will probably (inevitably?) find themselves, the question deepens consideration of a seemingly in-passing comment and brings it home / into the reader's experience.

The image of the sky that Kalanithi refers to in his narration of his time at the camp (light in one half, darkness in the other) can be seen as a metaphoric representation of what other aspect of his life – that is, of his whole life, not just of his life up to this stage?