Malcolm Young, the founder and rhythm guitarist of AC/DC, had begun showing signs of dementia when the band recorded the Black Ice album in 2008. The condition worsened, and — despite co-writing the songs with his brother Angus for the band’s new album, Rock or Bust — he does not appear on the disc. But he told Angus to keep the band going.

Before agreeing to that, Angus consulted with the rest of the band. He tells us, “Everyone was behind it. From that point I pretty much started putting together tracks and ideas for this album.”

Rock or Bust comes out tomorrow (Tuesday). Stevie Young, the son of Malcolm and Angus’s oldest brother, Stephen, took his uncle’s place on the album and will be in the lineup for next year’s tour.