Mervyn and Maree Schwartz, along with Maree’s adult son Graham Tighe were all found dead from gunshot wounds at the property near Bogie yesterday.
Graham had only just been introduced to his newborn son, his uncle told 9News.
The boy had been sick and was getting treatment in Brisbane Hospital so his father only got to spend a few days with him before he died.
Maree’s other son, Ross Tighe, survived and called police after being critically wounded.
The family, who had just moved into the sprawling $10 million property a year ago, had allegedly been locked in arguments with their neighbour about a fence boundary.
The man accused of pulling the trigger, Darryl Young, had arranged a meeting at the gate between the two properties yesterday morning, police said.
This afternoon the 59-year-old was charged with three counts of murder and one count of attempted murder.
He will appear at Proserpine Magistrates Court on August 8.
Earlier, Queensland Police revealed more details about how the tragedy unfolded.
The weapon used in the deadly shooting was a rifle, Mackay district Superintendent Tom Armitt said, and the alleged gunman was a long time resident in the area.