Health problems and death

In April 2014, Young became seriously ill and was unable to continue performing.
On 16 April 2014, AC/DC released a note stating that Young would be "taking a break from the band due to ill health".

However, singer Brian Johnson stated that despite earlier reports, AC/DC are not retiring:
"We are definitely getting together in May in Vancouver.
We're going to pick up guitars, have a plonk and see if anybody has got any tunes or ideas.
If anything happens we'll record it."

In July, Johnson revealed that Young was in hospital receiving treatment for an unspecified condition
and during May recording sessions had been replaced in the studio by guitarist Stevie Young, his nephew.
On 24 September 2014, the band's management announced that Young would not be rejoining the band.
Stevie Young continued to fill in for Malcolm on the band's 2015 Rock or Bust World Tour.

On 26 September 2014, The Sydney Morning Herald reported that Young had dementia and had been admitted
to a nursing home where he could receive full-time care.
A source close to Young was quoted in this article as saying that he had "complete loss of short-term memory".
Young's family confirmed four days later that he had dementia, saying that Young "is suffering from dementia
and the family thanks you for respecting their privacy"

In subsequent interviews, Angus stated that his brother had been experiencing lapses in memory and concentration
before the Black Ice project and had been receiving treatment during the Black Ice World Tour which ended in 2010.

Angus confirmed that although his brother did not play on the 2014 Rock or Bust album:
"He still likes his music. We make sure he has his Chuck Berry, a little Buddy Holly."
He added that AC/DC would continue according to his brother's wishes and standards:
"Look, even with his health, Malcolm was touring until he couldn't do it anymore."

In that same interview, Angus stated that Malcolm was rehearsing AC/DC's songs repeatedly before every concert
just to remember how they went.
In an interview with Guitar Player about Malcolm Young's songwriting credits in Rock or Bust, Angus stated,
"Malcolm kept doing what he could until he couldn't do it anymore, but I have all the material he was working on.
There were a lot of riffs, ideas, and bits of choruses. I'd fill things in to see if we had a song.
Every album we've ever done has been that way. There was always a bit from the past,
a bit from what we had that was brand new, and, sometimes, just an old idea that either Malcolm or myself
had worked on but we never finished. The songwriting process didn't really change,
except for the fact that Mal wasn't physically there.
So when it came to writing and putting stuff together, I had Stevie [Young] there with me.
You see, Malcolm was always a great organizer. He always kept track of the stuff we were writing together.
He'd record it, date it, make notes. My records — if you can call them that — are always chaotic.
So, this time, Stevie helped me organize a lot of what was there."

At the conclusion of the Black Ice World Tour, Malcolm was diagnosed with lung cancer.
It was treated at an early stage, so surgery was successful and the cancer was removed.
He also had an unspecified heart problem and wore a pacemaker.