I read this who knows how long ago so I'm not sure how much of this is accurate, but here goes:

Man who travels never staying in one place returns home because his grandfather (?) died and left him a house (?). When he gets to the house he meets two siblings, one a girl who's in love with her brother, and one a guy who's awkward and a writer. Eventually, the two guys become friends with man illustrating (?) his novels, but the sister gets jealous and seeing that man decides to leave the house to them and continue traveling which makes the bro sad and the sis feel guilty. Anyway, it ends with them all living together in the house.

Thank you.

It's Hanaibara.

Thank you!