On writing about Gus' father's Alzheimer's when she had no experience with the disease
I actually have been very pleased because a couple people who do have [experience with Alzheimer's] said they thought I must have. And I feel very comforted to hear that, in a sense, because I think that when you write about a disease with which you don't have personal experience, there's always a risk of it being very presumptuous. And if you get it wrong, you really have done something that crosses a line. You have to be very, very careful.
I have a child who has special needs, and I am very sensitized to this because when I read books that have fictional characters with conditions like her, or syndromes like hers, and they don't ring true, I feel invaded in a way. So it's been very important to me in my work, when I write about something like Alzheimer's, to really talk to people who have experienced that and try to get it right.
On how the book ends
I think with this story, by the end, it's taken on a little bit the shape of a classic tragedy in that you can't parse through where the responsibility is. But at a certain part, all the pieces have just come together and there's not going to be a happy ending here — it's just a downhill roll. I think of this as what Gus describes in the end as a series of "small collaborative sins;" that everybody's a little bit guilty, and nobody's very guilty.