The Stand by Stephen King
Stu was 7 when his father died. Shortly after Stu started working at 9 years old, Stu's youngest brother, Dev, died of pneumonia, and although that meant one less mouth to feed, Stu still felt guilt. His mother died of cancer months before he graduated high school, forcing him to turn down an athletic scholarship he was offered so he could work in the town's calculator factory to support him and his younger brother. Later in life, Stu's wife died of the same cancer that his mother had died of.