Dear Dana: That time I went crazy and wrote all 580 of my Facebook friends a handwritten letter

When Amy Daughters reconnected with her old pal Dana on Facebook, she had no idea how it would change her life. Though the two women hadn’t had any contact in thirty years, it didn’t take them long to catch up—and when Amy learned that Dana’s son Parker was doing a second stint at St. Jude battling cancer, she was suddenly inspired to begin writing the pair weekly letters.

When Parker died, Amy—not knowing what else to do—continued to write Dana. Eventually, Dana wrote back, and the two be...