Should one object to a brother who gets angry and raises his voice when he is rebuked for backbiting?

Denouncing evil is obligatory for whoever encounters it, based on the Prophet's (peace be upon him) saying: "Whoever among you sees an evil, let him change it." It is a communal obligation (fard kifaya), becoming an individual obligation (fard ayn) only for the one who alone knows about it or is the only one capable of changing it. For the one upon whom enjoining good and forbidding evil becomes an individual obligation, it is not lifted except due to inability, such as fearing harm to oneself, one's property, or one's honor. It is not permissible to abandon forbidding evil merely because one's voice might be raised, rather, forbidding evil is obligatory according to one's ability, as long as one does not fear significant harm.