Malcolm Young AC/DC had moved to Melbourne. In early 1977 they returned to Britain and began a European tour with Black Sabbath. While Bon Scott and Ozzy Osbourne quickly became friends, relations were less than cordial between the other members of the respective bands. In one incident, Geezer Butler pulled a knife on Malcolm Young. Towards the end of 1977, bassist Mark Evans was fired; purportedly to find someone who could sing backup vocals. Evans described disagreement with Angus and Malcolm as a contributing factor. He was replaced by Cliff Williams. In 1988, Young missed the majority of AC/DC's Blow Up Your
Malcolm Young 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 been diagnosed with 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