More than Blue (2018) on Netflix

A terminally ill man sets up his best friend, whom he has loved since high school, so that she will not be lonely after he passes away.

Cream, a bright personality with a dark streak, somehow manages to make a connection with the secretive K. As high-school classmates they share their loneliness, get close quickly, and fill the emptiness in each other. Cream moves into K's place and they depend on each other like a family or lovers. Years go by, and K works for a record company and Cream becomes a lyricist, but they still live together, neither a couple nor friends. Diagnosed with leukemia, K is hesitant to reveal his illness because he does not want to hurt Cream by leaving her alone. Not knowing any of this, Cream starts dating another man and eventually accepts his marriage proposal.