Three years ago, Katie McHugh — daughter of one soldier, sister of another — got a text from her younger sister. “Kelly,” it said, “you need to come home now.” Let McHugh tell you the rest of the story from that day in May 2010 — how she feared the worst for her brother, who’d deployed to Iraq, only to find out her father, Col. John M. McHugh, 46, had died in a suicide-bomb attack in Kabul, Afghanistan, on what was supposed to be a two-week visit. He left behind a wife, five children and, at the time, one grandchild.…