The cause of Lazenby’s death has not been revealed.
It comes seven years after the death of another of Cave’s four children,Arthur,whofell from a cliff in 2015.
Lazenby had been recently released from jail after he was found guilty of physically assaulting his mother in March.
A court heard that Lazenby kneed his mother,Beau Lazenby,in the face during an argument in her Collingwood home,which caused bleeding and bruising.
He was released on bail on Thursday on the condition he had no contact with his mother for the next two years.
His lawyer told the court he had been diagnosed with schizophrenia.