"Monica (Fenty) is moving in to keep an eye on her. Rihanna's dad, Ronald, was a crack addict. Monica's refusing to let her go down that path," a source told.
Rihanna was recently hospitalised after suffering from exhaustion and dehydration. She tweeted a picture of herself attached to a drip in a hospital.
However, after a brief stay in the undisclosed medical centre, the 24-year-old was discharged and allowed to fly back home.
One reason why she may be suffering with exhaustion is her extensive workout regime, with her trainer Harley Pasternake claiming she will even hit the gym in the middle of the night if necessary.
Spotted: Virat Kohli, Anushka Sharma and other celebs at Mumbai airport
Photos: Salman Khan's 'special friend' Iulia Vantur at a song launch
Photos: Hrithik Roshan, Anushka Sharma, other celebs dazzle at event
In Pictures: Sex scandals involving Indian politicians
Photos: Abhishek Bachchan and Farah Khan at Boman Irani's birthday bash