Bruce has been diagnosed with frontotemporal dementia, which is a fairly severe form of brain degeneration. Despite the diagnosis, we've received no indication that Bruce has died. Instead, he's simply spending all of his time with family and away from the public eye, in part because his diagnosis makes it impossible for him to act. Bruce's diagnosis was a tragedy for his many fans, but the actor is still alive.
Why do people think that Bruce might have died? The rumor started after a recent interview that Arnold Schwarzenegger, a friend and contemporary of Bruce's, gave to CinemaBlend. In the interview, Arnold discussed Bruce in the past tense in a way that confused some readers.
"I think that he's fantastic," the Terminator star said. "He was, always for years and years, is a huge, huge star. And I think that he will always be remembered as a great, great star."
"And a kind man," he added. "I understand that under his circumstances, health-wise, that he had to retire. But in general, you know, we never really retire. Action heroes, they reload."
This phrasing may have been confusing, but Arnold was simply referring to Bruce's movie career in the past tense, not the actor himself. Bruce is still alive, and when he eventually does die, it will be a major news story.