What should I do about my older brother who treats me badly, and my mother and all family members support him and blame me after my father's death?

Injustice is forbidden among people. Allah has forbidden it upon Himself, and injustice will be darknesses on the Day of Resurrection. Harming a Muslim falls under the ruling of forbidden injustice, especially between a brother and his brother. The best of Muslims is he from whose tongue and hand other Muslims are safe. Patience and endurance are advised, because patience has praiseworthy consequences.