Apparently the performer was preoccupied with discovering life beyond Earth.
He said: "We used to spend all weekend watching movies and talking about UFOs, looking out for them. Ri really believes there are UFOs."
Rorrey, who is launching a rap career under the name GQ, said that his sister may be the coolest person in the music industry at the moment but she was known for being extremely diligent at school in Barbados.
Rorrey Fenty told the Daily Star newspaper: "We worked very hard and took it really seriously. We went to good schools and Ri was a good student."
He added that she was very self-motivated and made sure she only took time out to have fun once a week.
He said: "She is very self-motivated so Mum didn't have to push her to do homework.
"She had a lot of discipline. We only went to the beach on Sundays."
