Someone cast a spell, or made an offering of five younger people to protect a soldier?
Honestly what else could it be? Say you have some kind of supernatural ability, and your husband, or son gets drafted. You think he has a fair shot of dying in the war. So you cast a spell to offer five deaths in return for his safe return. It works, but somehow the pattern repeats itself. You would think the very first thing the kids would do is try to research the first soldier that came back from the war, and see if his wife/mother/aunt/granny was the witchy type.