When I was a kid, and quite a few kids in my school district ended up dying of accidents, or cancers and other diseases, a good chunk of the kids who died were popular kids, rich kids, and/or athletes.
But in “issues” books for kids, at least during the 70’s and 80’s, the sick and unlucky kids were always unpopular kids, usually social outcasts due to their hobbies or their family’s socioeconomic position. You never had to see how other popular kids dealt with their popular friends having terminal illnesses, whereas in real life this happens fairly often (albeit usually in high school these days, not in elementary or junior high).
So yeah, this was probably part of my loathing of “issues” books from back then. The authors really were trying to kill off all of us funny-looking kids, and pretending that the popular could live untouched.