From MangaUp:
Kishibe Shino is a high school student. 17 years old. Her parents died, and then six months ago, so did her older brother, her only remaining blood relative. Now she lives with her “brother’s wife,” Nozomi-san. “We might not be blood-related but we’re family.” The story they write is a bit clumsy but full of something inexplicable. Slowly but surely, they happily grow together through their sensitive daily life.

Original Manga