Just days after Jack Osbourne reported his dad was "doing much better" after being hospitalized for flu complications, Ozzy Osbourne has been rushed to intensive care over concerns that he's developed pneumonia.

"Poor old Ozzy hasn’t had the best of times," an insider tellsThe Sun. "He’s been really struggling with flu which turned into bronchitis. Doctors feared he could contract pneumonia which, in a person over 70, can be fatal."

The development marks Osbourne's latest setback in his increasingly failing health. Prior to his hospitalization for the flu, he was treated for a staph infection and underwent surgery on his hand. In January, Osbourne ruptured a blood vessel in his eye from coughing too hard.

"Ozzy's a fighter and is getting better by the day," the source says. "The worst is over, he’s smiling again, and he can’t wait to get up on stage."

Should Ozzy get up on stage again? By continuing to perform when they've gotten old, do rock stars change the way people remember them?