Tom Brokaw’s latest book, “Never Give Up,” is a loving tribute to his family who headed west after the Civil War, and to other hard-working people of the Plains States whose stoic outlook built America’s Midwest. The former NBC newsman talks with “Sunday Morning” anchor Jane Pauley about his parents, how Brokaw himself found the origins of his own success in a tiny town in South Dakota, and how he has persisted against an incurable form of blood cancer.