His partner, Carol Radnoty, died last month.
Mr Radnoty's sister, Debbie Radnoty, said while it was expected Larson would be released from prison after serving a couple of years, noted: "It is not much (time) is it?"
"It was on the cards this was going to happen; we all got used to that idea, but I don't think anyone should only be given that much time."
The Parole Board noted Larson had completed the special treatment unit rehabilitation programme (STURP), which provides treatment to serious violent offenders with a high risk of re-offending.
He had a full-time job offer available following his release, and had been sitting his licences so he could be employed by the company.
The board raised concerns about Larson returning to using and abusing alcohol, and it was a condition that his residence be alcohol-free.
The board also noted Larson was on intensive supervision for offending relating to drink-driving and on a third and subsequent offence.
He had "previously demonstrated an inability to comply" with electronic monitoring, and also had breached community detention and court orders.
The board expected Larson, having done the Sturp programme and Drug Treatment Unite programme, would have the skills to deal with risk areas, and comply with his release conditions.
Larson would be on partial restrictions at his address - from 8pm-6am - for four months following his release.
This order would be reviewed by the board in December.
He was not to possess, buy or consume alcohol, while subject to parole conditions.