I searched this. They said he's doing ok and is back home.
Edit: I know it's tmz but still....
"
3:30 PM PST -- A rep for Prince tells TMZ, the singer has been fighting the flu for several weeks. He canceled 2 shows on April 7th but wanted to make Thursday night's performance in Atlanta, even though he was still not feeling well.
After the show, he got on a plane and felt considerably worse, so his plane made an emergency landing in Moline, Illinois, where he was taken to the hospital and treated. He was released 3 hours later, got back on the plane and is now back home."