Nearly a decade ago, my 80-year-old dad sensed quiet and a lack of activity upstairs and felt a worried edginess creep under his skin. He headed up the basement stairs and was about halfway toward the top when the doorbell rang. Standing outside were his neighbor and my mom. The neighbor found her wandering next door, on his driveway, appearing lost. She had her purse, but wore only slippers on her feet. Although it was December in Minnesota, she had no coat. When the neighbor asked what she was doing, she told him she was just going home. When the neighbor pointed ...