As an atheist, I too stopped and re-read that particular section to think how I felt about it.
In the end, we don't know the motivation of the nurse. Could be that the nurse isn't even religious herself, which is why she asked if Mooney believed in god first, and since Mooney said she does, the nurse tried to help her mentally in a way that spoke to her. If Mooney said she didn't believe in god, the nurse might have said something else.
I say this because as an atheist who used to work in elder-care, I've had many conversations with very religious old people, where I "play their game" because they respond better to it, and seemed happy about it. Even if I don't believe in god, talking with people as if I did, just makes sense in situations where people seemed to have lost all hope.