Craig Hackett has not responded to the unsubstantiated claims.
Hackett was arrested yesterday at his parents’ house on the Gold Coast.
Neighbours reportedly said that the 36 year old was "going off" and stabbing a knife into a chopping block before his arrest.
“The Grant Hackett that Australia fell in love with, they can still have that affection towards him,” Craig told reporters after his brother’s arrest. “This is not Grant Hackett. This is a completely different person. I don’t know this person, my mum and dad don’t know this person. He’s there in body, but he’s not there in mind, soul or spirit.”
Hackett’s father's Nev said his son has been arrested over “mental health issues,” reported the Courier Mail.
He was taken into custody by police but later released without charge.
