Futami Mio♀

A girl who was admitted to the hospital that the protagonist previously worked at. Her illness was unknown, an incurable disease with no treatment. She was discharged and able to live normally as long as she didn't have any fits. She feels affection towards the protagonist, who made eager efforts to cure her, but it is the feeling of a younger sister who depends too much on her older brother, not the feeling of love.

[Based on the official site]