The brothers were parted for the first time since they signed on at Old Trafford in 2008 when Fabio linked up with Queens Park Rangers during the summer on a season-long loan deal.
Despite admitting that he misses having his sibling around, Rafael concedes that Fabio's absence has helped him grow as a person.
"It's not strange but it's different," Rafael told MUTV. "We're close and I was always together with him but it's been good for us, just to become more mature.
"I used to ask him all the time if I needed something but now I need more of my own mind so I've grown more mature. It's bad because I miss him but it's good to learn more."
Rafael has been United's regular right-back so far this season, while Fabio is currently sidelined with a hamstring problem.