The 32-year-old man's knife attack at their Parramatta home in April 2020 followed other domestic violence after he accused his wife of having an affair.
The man's mother observed him being domestically violent towards his wife over disputes primarily related to financial problems, Parramatta District Court was told on Monday.
Early in 2020 she told her husband she wanted a divorce and he moved out of their house. But on April 17 that year he went back and accused his wife of having an affair, which she denied.
He threatened to kill himself, after killing her and their son. He hit his wife's face and when the boy tried to protect her, his father bit his arm.
Because of the suicide threat, his wife allowed him to move back into the house.
But on the night of April 24 after he'd been drinking they argued again, with him repeating the affair claim.
He picked up a kitchen knife and when his son asked why he had it, the six-year-old was stabbed twice in the chest. Hearing her son's screams the woman saw her husband holding the bleeding boy and knife, as the son said: "Daddy don't do it".
The father then stabbed his wife's stomach - damaging a kidney, her pancreas and causing her to have her spleen removed in surgery - and twice on the arm.
She told her son to run and he went outside calling for help. That made the man panic, enabling his wife to grab the knife and throw it away.
A neighbour responding to the calls, went to the front door and told the man to let his wife go.
He fled, with CCTV footage later showing him walking barefoot through Parramatta streets before handing himself in at the police station.
Judge Stephen Hanley said the attacks were "unprovoked" and left his wife with long-term physical and psychological impacts.
"The motive appears to be to punish his wife because she said she was leaving him. I accept it was not premeditated," he said.
The young boy's wounds treated in hospital were not as serious, but "psychologically extremely damaging".
"He remains fearful his father will escape from prison and attack him," the judge said, citing the boy's victim impact statement.
The man was diagnosed with a major depressive disorder at the time, partly as a result of his import business failing, which led to his consumption of alcohol.
But the judge said that had only a limited impact on the seriousness of the offending behaviour.
The man, who had pleaded guilty to offences including causing grievous bodily harm and reckless wounding, had his seven-year jail sentence backdated to April 2020 when he first went into custody, with a non-parole period of four years.
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