The Black Sabbath vocalist reveals that the guitarist's continuing health issues will limit their touring ability for the foreseeable future � but he's still fared better than wife Sharon during her own illness.

Osbourne tells Rip It Up: "Tony's fine, but he can only go out on the road for six weeks at a time. He has to have infusions or some sh*t for his immune system.

"I was amazed that during his chemotherapy he was still writing songs. My heart goes out to him, because when Sharon had cancer a few years back, she was so sick from chemotherapy she could barely get out of bed. It's like having a football kick to the nuts.