A Sydney boy whose father is accused of murdering his mother in a house fire told police he woke to hear his mum screaming his name and saw a burning blanket near her bedroom door, a jury has heard.
"I just woke up, I saw the fire, I was so shocked," the then nine-year-old said during a video-recorded police interview after the fatal 2016 blaze.
He pressed tissues to his eyes when he recalled hearing his mum calling out his name.
"I couldn't do anything," the boy said.
His interview was played to a NSW Supreme Court jury on Tuesday during the trial of his father, who can't be named for legal reasons.
The 45-year-old, who pleaded not guilty to murder, is accused of using petrol to light the western Sydney house fire which burned his wife to death.
During the police interview, the boy recalled unsuccessfully trying to open his mother's door with his brother and father by pushing or pulling it "like in the movies".
His father called triple-zero from outside the house and put water on it with a hose, the jury heard.
"He tried helping as much as he could," the boy said.
He said his mother and father had verbally fought over use of the mobile chat application Viber but he never saw them punching or kicking each other.
Asked how he felt about his dad, the boy said he was kind to him but not his mother.
He cried when he told the police officer he thought his mum "passed away".
Crown prosecutor Christopher Maxwell QC previously told the jury he expected evidence that the accused prevented the boy from opening the door and "kept pushing" his wife into the fire.
But defence barrister Carolyn Davenport pointed to the son's testimony about his father helping as much as he could.
"It's not all one-way," she said during her opening address, adding that consideration should be made to a radiant heater in the bedroom.
The son during his police interview said on the night of the fire, before he went to sleep, he saw there was a heater on.
The trial continues.