Sumathi (26), a resident of Veppilankurichi near Neyveli, and her father bore the brunt when they tried to mediate in a quarrel between a man and his wife on Friday.
Police sources said that when Gnanavel (45) indulged in heated exchanges with his wife, Sumathi and her father Nagaraj intervened and volunteered to bring about a compromise between them.
Instead of listening to their advice, Gnanavel turned his ire against them.
Later, he and his brother Gnansekaran joined hands and attacked Sumathi and her father with broken beer bottles.
The injured have been admitted to the Vriddhachalam government hospital.
The police are on the lookout for the siblings.
