The knife, which had a five-inch blade, pierced the man's liver, leaving him with severe internal bleeding and he had to undergo life-saving surgery, York Crown Court heard.
Alan Goddard, 19, was angry when he saw his sister upset, following an argument with her partner over money.
Goddard went round to confront the man at his home in Acomb, which he shared with the defendant's sister and three young children , on the evening of September 7, last year.
Once inside the house, an argument followed and Goddard hit the victim a number of times with a wooden bed leg, before pulling out a kitchen knife from his jacket pocket.
Prosecuting Matthew Collins said: "Matters had spiralled dramatically.
"The defendant thrust the knife into his torso, leaving it there and letting go of the handle before running out of the house.
"The victim managed to get the blade out and the wound began gushing blood."
The man managed to get help from his neighbour and an ambulance was called. He was taken to Leeds General Infirmary for emergency surgery to stem the internal bleeding.
In a victim statement, summarised by Mr Collins, the man said the attack had a significant impact on both his physical and mental health. The father-of-one said he had to move away to a different area as a result of what happened.
Goddard pleaded guilty to wounding with a knife and possession of a bladed article at an earlier court hearing.
In mitigation, Ben Campbell, said Goddard was "filled with remorse" for what had happened and that he had "no previous experience of the criminal justice system".
Mr Campbell said Goddard had a difficult upbringing and had been expelled from school when he was in year 10 and as a result attended a special school, where he was a victim of bullying.
He said Goddard had no "specific diagnosis" of being on the autistic spectrum but had displayed characteristics of this.
Sentencing Goddard to six-and-a-half years in prison, His Honour Judge Simon Hickey said: "This escalated from an innocent verbal argument which spiralled out of control and led to man receiving life-changing injuries."