A northern NSW man badly injured when a rock went through his windscreen has told a court it was an unforgivable and cowardly attack.

A NSW tradesman has told how a carload of rock-throwing youngsters hijacked his life in a terrifying attack that doctors believed he had little hope of surviving.

But Patrick Garrett did survive, and on Tuesday he faced two men accused over the “cowardly” and unprovoked attack.

Robert Joseph Jackson was sentenced in the Downing Centre District Court to 10 years jail while Kelvin Mark Muckan pleaded guilty to two offences including grievous bodily harm.

Mr Garrett told the court he was driving to his home in the small country town of Guyra near the NSW/Queensland border with his father in spring 2012 when a rock smashed through the windscreen – and through his skull.

Mr Garrett slumped over, bleeding and unconscious, as his father tried to wrest control of the car from the passenger seat.

“In those few seconds, everything I was and my future were absolutely changed,” Pat Garrett said in a sentencing submission read to the court on Tuesday by his brother Shane.

“I can’t imagine the terror that my family must have felt: me unconscious, lying on dad’s shoulder, him trying to control and stop the car and when he finally did, the sight of me unconscious with a gaping hole in my head, bleeding profusely – no mobile reception and in the middle of nowhere.”

He told the court the attack destroyed his sense of smell, he is now forced to rely on Centrelink payments and he rarely goes out with friends.

“I am angry that my life has been hijacked,” Mr Garrett’s statement said.

“It was a cowardly act … What you have done to me is unforgivable.”

Members of the public gallery sobbed as Jackson, a 22-year-old Queenslander, was sentenced for his role in the attack.

He will not be eligible for parole until November 2018, this despite evidence from Jackson’s father that he was a “follower, not a leader”.

Judge Reg Blanch said it couldn’t be demonstrated that he had thrown the rock that struck Mr Garrett, but there was no dispute that he knew the rocks were in the car and “there was a common purpose to use them”.

“It has to be said that it is an astonishingly reckless and irresponsible course of behaviour on the part of all the offenders,” Justice Blanch said.

“It has had some dire consequences for perfectly innocent people going about their ordinary lives.”

A third man has already pleaded guilty over his role in the attack and is due to be sentenced on Wednesday.

Two other people have pleaded not guilty, and are expected to stand trial next month.