My Heart Can't Beat Unless You Tell It To (2020) on Netflix

Plot summary

Dwight and his sister Jessie care for their younger brother Thomas, who is chronically ill, cannot go outdoors in daylight and survives on blood. The two of them keep him fed by killing strangers, mostly people who are homeless or drifting through. Jessie works as a waitress in a local diner, and Dwight raises money by selling things he picks up around town or takes off the people they kill. Dwight pays Pam, a prostitute, for a few extra minutes of talk after their time together. After one murder turns especially grisly, Dwight begs Jessie to find Thomas real medical help. She refuses, and instead orders him to bring home another victim.