Because death is not about the ones passing away. It's about the grief and torment that plagues and eats away at the hearts of the ones left behind.
***
THIS SHORT STORY IS TOLD FROM DEATH'S POINT OF VIEW.
Prioritizing her oldest friend was something she sucked at, she knew that but she also knew that at least twice a year she had her priorities right and put her oldest friendship before all else... it wasn't enough not nearly but it was all she managed and once she realized it was too little, it was already too late and she'd never forgive herself for not having been a better friend to him.