Young, whose retirement from the band was announced earlier this week, has been moved to a full time care facility in Sydney.
Rumours about the health of Malcolm Young, founding member of one of music's all-time biggest selling acts, had been swirling since earlier this year when reports emerged that he was no longer able to remember how to play many of AC/DC's signature songs.
Amid rumours of his failing health, AC/DC issued a statement saying that he would not participate in the recording or touring of the band's next album 'Rock or Bust', due later this year. The news of his admittance into a care facility, though, is the strongest indication yet of Young's current wellbeing.
The Sydney Morning Herald quotes a source close to the Young family, saying: "If you were in the room with [Malcolm] and walked out, then came back in one minute later, he wouldn't remember who you are. He has a complete loss of short term memory. His wife, Linda, has put him in full-time care."
AC/DC have sold upwards of 200 million albums since they formed in 1973 and Young, whose brother Angus also plays guitar in the band, was crucial to their songwriting and playing style.
The 61-year-old will be replaced in the band by his nephew Steve ahead of a tour next year.