Jack Osbourne had to convince his father Ozzy Osbourne and mother Sharon to chronicle the rocker’s Parkinson’s disease battle in his new documentary to avoid “lying” to fans.The former Black Sabbath frontman gets candid about his long struggle with substance abuse, trouble with the law, and marital issues with his manager wife Sharon in The Nine Lives of Ozzy Osbourne – but one thing the singer wasn’t ready to open up about was his most recent health diagnosis.Jack, who serves as a producer on the film, reveals his parents were reluctant to go public with the health news on camera, despite learning he was suffering from the progressive neurological condition in early 2019, while the project was in the midst of production.“I had to kind of