Young stepped away from the band that year due to ill-health, with his nephew Stevie Young substituting on rhythm guitar on the Australian hard rock legends' Rock Or Bust world tour. It was later revealed that Malcolm Young had been diagnosed with dementia. Young passed away on November 18, 2017.
Writing in his just-published memoir The Lives Of Brian, Johnson mourns the guitarist's passing.
"He was just sixty-four when the dementia that he'd been battling for years finally got the better of him," he writes. "A truly awful day."
"When Malcolm left AC/DC in 2014, the heart of the band stopped beating. To this day, I miss him more than I could ever put into words. He never missed a trick, from a band member's performance to a crew member's well-being. I don't know how he did it. He had his demons, but he beat them, and he beat them good. His guitar playing was masterful. And behind that powerful sound, there was a subtlety that music critics could never understand. Standing to his right onstage, I could only ever marvel at the man. But I kept my admiration to myself for the most part because he wasn't the kind of guy who enjoyed taking a compliment.
"It was hard to see Angus struggle with such grief. He and Malcolm weren't twins, but they could have been."
After being forced to step away from AC/DC due to hearing loss, Johnson returned for the triumphant Power Up album, which reached Number 1 in 21 countries.
"We all had a point to prove," Johnson writes. "We were the originals. We wanted to show what we could do."
The Lives Of Brian is out now, published by Penguin Michael Joseph in the UK, and Dey Street Books in the US.