My daughter had just learned she would have to endure still more chemotherapy for her leukemia. A tear welled up in her eye. But she quickly stopped herself, and her steely resolve returned. “If Ben can go through everything he’s had to deal with,” she said, “I can do this.” Amy kept her commitment, with flying colors. So did Ben. Ben Rubenstein is a cancer survivor nonpareil and author of Twice: How I became a cancer-slaying Super Man before I turned 21. It’s a book that every cancer patient should read. So should every member of families dealing with cancer,...