Shitsurengo, Kenaku datta Osananajimi ga Satougashi Mitai ni Amai: Bitter nochi Sugar

Yuu Sawatari, a high school boy, is sick after suffering a painful heartbreak. His nextdoor childhood friend, Cocoa Shirayuki, shows up to take care of him. From that day on, the distance between them grows closer... This is a tense, sweet, and slightly heartrending love story of a boy who has lost...

Source: MyAnimeList