Leopold Purer's victim impact statement was read before a Supreme Court sentence hearing on Thursday for his 21-year-old grandson, Bradley Craig Mottram, who has pleaded guilty to murder.

Mottram was 19 when he repeatedly stabbed his 51-year-old mother, Simone Mottram, at her Inverell home in October 2015.

In October, last year, The Leader revealed the then-teenager stabbed his mother in a frenzied attack, placed the knife on her body and covered her before fleeing the Froude Street house, leaving his blood-stained footprints at the scene.

Mr Purer's statement says he nearly collapsed and was in disbelief when police told him his daughter was dead and his grandson had been arrested.

More than two years on, his pain and sadness are greater than ever and he's "tortured by intrusive thoughts" and "nightmarish images".

"It has been shocking to discover in myself a depth of anger so corrosive that it makes me capable of having violent thoughts of retribution against my grandson," Mr Puer said. 

"Once I would have thought such a thing impossible."

Ms Mottram's partner, Robert Hawke, is constantly reminded of what happened at their home because pieces of blood-stained carpet were removed by crime scene cleaners.

"I can't afford to have the carpet and floor fixed and can't afford to sell the house to start afresh," he said.

Simone's mother, Maureen O'Bryan, says since her daughter's death she's had difficulty envisaging her over the age of two to three.

When she tries to visualise her as a woman she only sees images of her violent death.

Mottram is scheduled to be sentenced by Acting Justice Peter Hidden in June.

Mottram has been in custody since the day of the murder after he crashed his mother's car, out of Inverell. 

 – Australian Associated Press