The Strawberries and the Gun (2007)

Older brother Kenichi and younger brother Takashi had not seen each other for a while, but they meet at their estranged father's funeral. The father had moved to a small town and remarried and has a daughter, who is supposed to be their half-sister. Her whereabouts are unknown, as she left home at a very young age. One of the brothers mistakenly meets her, under very strange and disturbing circumstances...

Unfortunately the movie The Strawberries and the Gun is not yet available on HBO Max.