When most mothers worried about their sons, it was so often the most trivial of life's problems. Did he clean his room? How's he doing in school? Is he feeling all right?
Some of the most common. It was different for Sally Jackson.
While other mothers worried about their son missing lunch one day because of a project or whatnot, she worried about her son starving on a quest because supplies ran out. While other mothers worried about their son's math skills, she worried about her son keeping up with swordfight practice. While other mothers worried about their son getting a cold, she worked about her son getting killed.
But those were the reasons she cared so much - more than those other moms would for their sons - when Percy came home.