WASHINGTON — Mitt Romney was, uncharacteristically, terrified.
It was the fall of 1998, the height of Mr. Romney’s high-flying career as a private equity executive. But his wife, Ann, was not well. She was exhausted, and having difficulty walking; her right foot was dragging. When a neurologist at Massachusetts General Hospital arrived at a diagnosis — multiple sclerosis — “they just held each other in their arms,” their son Josh said, “and just cried.”