According to Rolling Stone, legendary guitarist, songwriter, brother and co-founder of the Australian rock band AC/DC has passed away at age 64. Malcolm Young, the long time rhythm guitarist for the band had been struggling with dementia for the past three years and finally succumbed to its effects Saturday. “Today it is with deep heartfelt sadness that AC/DC has to announce the passing of Malcolm Young,” AC/DC wrote in a statement. Young’s older brother and AC/DC producer George Young also passed away this year in October.

Young contributed to much of the success of the Rock and Roll Hall of Fame-inducted band, since their debut album High Voltage in 1975 to 2014’s Rock or Bust. That was the last year Young played live with AC/DC and the final album he co-wrote, as he announced in September 2014 that he would be permanently leaving the band due to dementia.

“Malcolm, along with Angus, was the founder and creator of AC/DC. With enormous dedication and commitment he was the driving force behind the band. As a guitarist, songwriter and visionary he was a perfectionist and a unique man. He always stuck to his guns and did and said exactly what he wanted. He took great pride in all that he endeavored. His loyalty to the fans was unsurpassed.

As his brother it is hard to express in words what he has meant to me during my life, the bond we had was unique and very special. He leaves behind an enormous legacy that will live on forever. Malcolm, job well done.”