Cara Pressman sobbed in the big red chair in her living room. The 15-year-old tried to absorb the devastating news relayed by her parents: that their insurance company, Aetna, denied her for a minimally invasive brain surgery that could end the seizures that have haunted her since she was 9 years old. “When my parents told me, I went kind of blank and started crying,” she said. “I cried for like an hour.” Her friends had been lined up to visit her in the hospital for the surgery three days away, on Monday, October 23. Between tears, she texted them...