Chris Brown's mother "loves Rihanna like a daughter".
Joyce Hawkins hasn't seen the 'Umbrella' singer since her son assaulted her in February, and she claims she misses her every day.
Joyce said: "I love Rihanna. She's like a daughter. She became family to us. She's spent Christmas with us for the last two years. I miss her a lot."
Chris attacked Rihanna in his car as they left a pre-Grammy Awards party, repeatedly punching her in the face and biting her arms.
He later pleaded guilty to assault and was sentenced to six months of community service, 12 months of domestic violence counselling and five years probation.
The judge also issued a restraining order which requires him to stay at least 100 yards from Rihanna for five years.
Chris - who recently admitted he was still in love with Rihanna - said the punishment was "fair".
But the rapper was not so pleased with talk show host Oprah Winfrey's Rihanna-inspired episode on domestic violence that aired earlier this year, claiming he found it insulting.
He complained to People magazine: "I commend Oprah on being like, 'This is a problem,' but it was a slap in my face. I did a lot of stuff for her, like going to Africa and performing for her school.
"She could have been more helpful, like, 'OK, I'm going to help both of these people out.' "
A spokesman for Winfrey replied: "Oprah is very appreciative that Chris Brown performed at her school, but she takes domestic abuse very seriously. She hopes he gets the counselling he needs."