Son who killed his abusive father by pushing him down the stairs during row over wasting water walks free from court after admitting to manslaughter

A Brisbane man who killed his abusive and volatile father during a bitter argument over 'using less water' will walk free from jail after being granted immediate parole.

Timothy Howard McCaffrey, 45, pleaded guilty in the Supreme Court on Tuesday to the manslaughter of his father, David McCaffrey, 69, at Clontarf northeast of Brisbane.

The court was told the father and son had a long history of animosity which boiled over when Mr McCaffrey Snr stormed into the front yard where his son was watering, berating him for using too much water in April, 2018.

The court was told Mr McCaffrey Snr yelled at his son, fuming over the cost and amount of water he was using before going inside and slamming the door to the two-storey home.

Brisbane man Timothy Howard McCaffrey, 45, walked free from the Supreme Court after pleading guilty to manslaughter after pushing his dad down the stairs during an argument (stock image)

The argument continued as Timothy McCaffrey followed his father inside, confronting him on the stairs - yelling 'you deranged bastard' before grabbing his father by the throat.

He then shoved his father causing the older man to stumble, losing his balance and falling backward down the stairs.

Timothy McCaffrey was twice the size of his father who weighed just 54 kilos at the time of the accident.

There was a loud crack when the 69-year-old's head slammed into the concrete at the foot of the stairs, and he 'twitched and squirmed' and stopped breathing.

Timothy McCaffrey performed CPR to revive his father before he was taken to hospital with critical head injuries where he admitted to police 'if he's dead, I'll be happy'.

Mr McCaffrey Snr never regained consciousness and died when his life support was switched off just over 12 hours after the accident.

A psychologist's report found a history of domestic violence within the family, with Timothy, his mother and sister all physically and verbally abused over a 'harrowing' period of more than 40 years.

During a previous assault, Timothy McCaffrey broke several of his father's ribs to stop him physically abusing his mother who was in court to support her son.

The Supreme Court heard Mr McCaffrey Snr's head hit the concrete at the base of the stairs and he never regained consciousness before dying in hospital 12 hours later

After his father's death, Timothy McCaffrey said he never intended to kill him.

'I did not mean to kill him, I didn't mean it to happen, it was an accident,' he told police.

He wrote a letter to his father saying 'I forgive you Dad, I hope you can forgive me'.

Justice Thomas Bradley described Mr McCaffrey's death was a 'terrible tragedy', accepting his son could not 'intend or foresee' it would lead to his father's death.

'You had had many decades of living with the knowledge and the consequences of your father's wholly inappropriate acts of violence and intimidation toward your mother, yourself and your sister,' Justice Bradley said.

He imposed a sentence of five years' imprisonment to be immediately suspended with his two-and-a-half years in custody as time served.

His mother wept quietly during the sentence and smiled as the Justice Bradley ordered her son's immediate, telling AAP outside court she was 'thrilled' with the result.