Also---The Road by Cormac McCarthy. It concerns holding onto family values (a father and a son) in the face of the ultimate desolation and bleakness of the ashes of America.

Also, along those same lines, albeit, this time a desolation caused by a nearly total plague --- EARTH ABIDES by George R. Stewart. It, too, focuses on the few survivors.
It is only the best science fiction book ever written me thinks.

Art Thieme