( RollingStone.com ) -- The family of founding AC/DC guitarist Malcolm Young has confirmed the illness that forced the 61-year-old to quit the band . `` Malcolm is suffering from dementia and the family thanks you for respecting their privacy , '' they said in a statement , according to People . RS : The 10 Best Metal Albums of the 1980s . The group had previously announced in April that Young would be taking a break from the band and that it would be recording a new record without him . When AC/DC announced that it would be putting out the record , `` Rock or Bust , '' this fall , they confirmed that Young would not be returning to the band , `` due to the nature of Malcolm 's condition . '' They did not go into the specifics of the illness . Young 's nephew , Stevie Young , played rhythm guitar in Malcolm 's stead on `` Rock or Bust . '' He will also be filling in for the elder Young on the group 's upcoming world tour in 2015 . RS : AC/DC release entire catalog on iTunes . `` We miss Malcolm , obviously , '' AC/DC frontman Brian Johnson told Classic Rock in July at a time when the band was optimistic about the guitarist 's return . `` He 's a fighter . He 's in ( the ) hospital , but he 's a fighter . We 've got our fingers crossed that he 'll get strong again . ... Stevie , Malcolm 's nephew , was magnificent , but when you 're recording with this thing hanging over you and your work mate is n't well , it 's difficult . But I 'm sure ( Malcolm ) was rooting for us . '' RS : Hear Malcolm and Angus Young 's very early single . `` Rock or Bust '' will feature 11 new AC/DC songs when it comes out on December 2 . In September , the band began teasing the song `` Play Ball '' in ads for Major League Baseball 's Postseason campaign on Turner Sports . ( Turner Sports is a division of Time Warner , as is CNN . ) See the original story on RollingStone.com . Copyright © 2011 Rolling Stone .
Malcolm Young will not be returning to AC/DC . Founding band member is not on forthcoming album , `` Rock or Bust '' due out in May.