Tia Minhinnick has been sentenced to 21 years in prison for murdering his mother, 41-year-old Angela Huata, at their home at Springvale in Melbourne's southeast in February 2022.
Minhinnick, who was aged 20 at the time, had a "highly conflictual" relationship with his mother in the lead-up to the attack.
He had spent the night drinking with friends and acting erratically, punching and headbutting his friend outside, before returning home.
The belief that his mother was mistreating his baby sister mixed with a cocktail of alcohol and drug-use prompted the "vicious assault" on the night of February 9.
His housemates arrived home before midnight to find him standing over and yelling at his mother, who was sitting on the lounge room floor bleeding from her forehead.
Minhinnick's housemates retreated to their room after he threatened them when they tried to help his injured mother but they did not call police out of fear.
He was heard on a neighbour's audio recording yelling, "get the f*** up, get the f*** out" as he continued his assault.
At some point, Minhinnick shifted Ms Huata from the lounge room to the garage where he continued the attack before eventually putting Band-Aids over lacerations on her nose and chin.
He wrapped a bandage around her head and, just before 1.30am, messaged his girlfriend Natalie Jensen, saying: "I think I might of went too far".
Jensen phoned police about 12.15pm on February 10, lying and saying she'd just arrived at the house before performing CPR on Ms Huata.
Justice Richard Niall described the attack on the vulnerable mother as "protracted, extremely violent and unrelenting" in his sentencing remarks on Monday.
"She was a victim to your shocking behaviour," he said.
Ms Huata had been stripped naked and was declared dead at the scene with authorities finding 29 separate rib fractures, burst eardrums, a laceration to her liver and a brain injury among other injuries.
Minhinnick shook in the Supreme Court stand and stared towards the floor as the judge summarised the case and said a long term of imprisonment was inevitable.
"The sentence I must impose on you (will see a) large proportion of your 20s and 30s spent in prison," he said.
"It is a significant punishment."
Minhinnick will be eligible for parole once he has served at least 15 years of his sentence.
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