Rockers AC DC are planning to keep it in the family when it comes to replacing guitarist Malcolm Young in the line-up - his spot will be filled by his nephew.

Young's family and the band's former manager Michael Browning have confirmed reports the rock star brother of bandmate Angus Young has dementia.

He is reportedly being treated in a nursing home in Sydney, Australia, and has pulled out of all band activities to concentrate on his health.

Browning says, "I think it (Young's illness) came on very suddenly... It's shocking. It's terrible. Sadly for Ac Dc, they're losing their creator, their mentor. He's the genius behind the band."

Young did not participate in the recording sessions for Ac Dc's new album, Rock Or Bust, and he was replaced by his nephew Stevie Young, who is expected to join the band for its upcoming world tour.