A man who inflicted horrific injuries on his elderly parents during a brutal, seven-hour attack at their Mount Pleasant home has been jailed for a maximum 17 years.
Dressed in his prison greens and sitting silently in the dock, Matthew Charles Welch showed no emotion as Wollongong District Court judge Paul Conlon sentenced him to a maximum 17 years in jail, with a minimum non-parole period of 12.
Judge Conlon handed down the hefty sentence on Tuesday, after detailing Welch's "cowardly, callous and sustained attack" on his adoptive parents, Peter and Desley Welch, who were 83 years old at the time.
The court heard the 48-year-old savagely attacked the pair over a seven-hour period in their Rose Parade home on April 5 and 6, last year.
During that time he kicked and punched them repeatedly, hit his father over the head with a bottle of Cointreau, destroyed the phones, ransacked the house and refused to let his father call the hospital for help.
"Not satisfied with inflicting considerable physical pain and injury, his conduct was calculated to make the victims suffer psychologically," Judge Conlon said.
"He brandished a sword and knives and started a fire close to where they lay on the floor.
"He threatened them that they were going to die [and] as they laid seriously injured on the floor, he humiliated them [by] pouring litres of milk over them."
As a result of the attack Peter Welch suffered fractured vertebrae, a bone-deep open wound on his left shin and serious head injuries.
Desley Welch, who was found unconscious with her face "black and blue", had severe bleeding on the brain and underwent surgery to remove part of her skull.
In a victim impact statement tendered to court, Peter Welch spoke of the devastating impact the attack had had on their lives.
"Prior to the assault, my wife Desley had a lovely, outgoing personality with a very natural ability to communicate . . . we have been married for 55 years," he wrote.
"Now Desley cannot walk and is confined to a wheelchair . . . [and she] is unable to talk except for the occasional word, so her communication with me and other close friends has all but ceased.
"The fact that our own son could have carried out such a brutal and unprovoked attack on us has been totally devastating," he said.
Judge Conlon said Welch showed "not a hint of remorse" for the horrific crime, particularly when he told police "Payback's a bitch" when told his mother might not survive the attack.
Judge Conlon also rejected the argument Welch attacked the pair because of past abuse or mistreatment, saying he had provided very little detail to support that claim.
Welch, who had several assault convictions on his record dating back to 1986, had a history of illicit and prescription drug use and had been diagnosed with depression.
He will be eligible for release to parole in 2025.