Everything you need to understand or teach The Good Husband by Gail Godwin.
The Good Husband's themes connect directly to its primary concerns, yet they are difficult to pin down. Insofar as the novel is an examination of howto-die or what-death-is, its theme is extremely opaque. Death itself is opaque, true, to all of us who have not passed this "final examination." But most novels about death present a theory or statement about it, which can range from saccharine reassurance to bitter nihilism. Godwin does not seem to have any such statement.
It may be that Magda's "ordering of her loves" is another way of saying, "At the end, all we have is love." As she fades, Francis, who devotedly loves her, cares for her tenderly long after outside events stop having any meaning. And Alice, whose loving friendship developed after Magda's illness, is there at the end like a benediction.
Yet the theme may be: "One dies as one lives...