The concerned father said if it were up to him, his daughter would leave Brown, 19, in the wake of last weekend's alleged assault, People.com reported Saturday.
"If it were me, I'd move on," the elder Fenty said regarding Rihanna, whose full name is Robyn Rihanna Fenty.
"You think you know somebody, but you really don't," the 55-year-old added, referring to Brown.
Brown was arrested following the alleged Feb. 8 incident in Los Angeles and could face criminal charges.
Fenty also said Rihanna, 20, would soon speak publicly about the alleged assault.
"At some point, she will speak out. I hope she will stand up for women all over the world," Fenty told People.