Authorities in Florida say a man claims he was forced to fatally shoot one of his adult sons in an effort to save another son.

According to People, the domestic disturbance reportedly occurred early Sunday morning at a family home in Stuart.

Police believe 56-year-old John Maloney shot 30-year-old Joseph in the head when the younger man put his younger brother in a headlock and threatened him with a large knife.

John’s wife, Marie, reportedly called authorities to the scene, describing her son’s “irrational” behavior and requesting him to be detained according to the state’s Baker Act.

John and Marie said they had been forced to barricade themselves inside their bedroom. Joseph began using a machete to try to break down the door as 26-year-old James, his brother, attempted to stop him.

The two brothers had reportedly argued over a billiards game during a night of drinking.

After witnessing the older son attack the younger with a “rather large butterfly knife,” police say John fired the shots that killed Joseph.

The son was pronounced dead after arriving at an area hospital, according to the Atlanta Journal Constitution.

One relative reportedly told police about an upcoming criminal trial in which the deceased was to face charges of DUI manslaughter and vehicular homicide in connection with a 2015 crash.

Martin County Sheriff William Snyder described the father as “shattered,” noting that he was not arrested in connection with the shooting.

“I don’t know that there’s any way for me to adequately describe the look on his face,” Snyder said of the shooter.

[Featured image: Joseph Oliver, Clayton County Sheriff’s Office]