Jamie and his sister DeOndra are featured in the latest issue of People magazine.
“She’s a superstar now,” Foxx, 43, tells PEOPLE in an exclusive interview in this week’s issue.
“One thing people may not understand is that the love a person with special needs gives you is unfiltered,” Jamie says of their strong sibling bond.
“There is nothing in the way of them loving you and there is nothing in the way of them being upset with you either. You really get the true individual.”
As for DeOndra, who lives with Foxx in Los Angeles, she is grateful for her Oscar-winning brother’s support.
“I’m happy to have a big brother to count on, who I love every day,” she says.