Mariah Carey's older brother is suing the star for defamation and emotional distress caused by her recent memoir, The Meaning Of Mariah Carey.
Morgan Carey, who is seeking unspecified damages, says the book falsely suggests he was violent.
As a result he has suffered "extreme mental anguish" and "serious damage to his reputation", his legal case says.
The papers have been filed a month after Mariah's sister sued her for $1.25m (£900,000) over the memoir.