Malcolm Young Dementia Update: One of the founding members of AC/DC, Malcolm Young, was diagnosed with dementia.  After four decades with AC/DC, Malcolm Young, is leaving the band. 

The group announced in April that Young would be taking a break and that AC/DC would be record their new record without him.

AC/DC put a statement on their Facebook page at the time, saying "After forty years of life dedicated to AC/DC, guitarist and founding member Malcolm Young is taking a break from the band due to ill health. Malcolm would like to thank the group's diehard legions of fans worldwide for their never-ending love and support. In light of this news, AC/DC asks that Malcolm and his family's privacy be respected during this time. The band will continue to make music."

The Sydney Morning Herald reported that the 61-year-old AC/DC guitarist is being treated at the Lulworth House care facility in Sydney, Australiam as his condition deteriorates. AC/DC confirmed the news to People that Malcolm Young has dementia.

AC/DC just recorded their 17th studio album, "Rock or Bust, which will be released on Dec. 1 

AC/DC's label confirmed that, "Unfortunately, due to the nature of Malcolm's condition, he will not be returning to the band." 

People shared a statement from the Young family saying "Malcolm is suffering from dementia and the family thanks you for respecting their privacy." 

A source the Sydney Morning Herald, "If you were in the room with (Young) and walked out, then came back in one minute later, he wouldn't remember who you are. He has a complete loss of short-term memory. His wife, Linda, has put him in full-time care."

Young's nephew Stevie Young will play guitar in Malcolm's place.

"Stevie, Malcolm's nephew, was magnificent, but when you're recording with this thing hanging over you and your work mate isn't well, it's difficult. But I'm sure he was rooting for us. He's such a strong man. He's a small guy but he's very strong. He's proud and he's very private so we can't say too much," Johnson said.

"Rock or Bust," AC/DC's new album, first album in the band's 41 year history without founding member Malcolm Young, "Rock or Bust," will be released on December 2. "Rock or Bust" is AC/DC's first studio album of all new material in six years. 

Brian Johnson reportedly wanted to name it "Man Down" as a tribute to , Malcolm Young.

AC/DC will go out on a world tour in support of "Rock or Bust" staring in 2015.  Joining the band on tour will be the nephew of founding members Angus and Malcolm Young, Stevie Young. Young played rhythm guitar on "Rock or Bust."

AC/DC was put together in November 1973 by brothers Malcolm and Angus Young. They moved to Australia from Scotland in 1963. Brian Johnson replaced Bon Scott, AC/DC's original lead singer who died on February 19, 1980. Scott died of "acute alcohol poisoning" after partying all night at the Music Machine club in London. Brian Johnson joined for AC/DC's Back in Black album.