Jed Beaumont had defeated brain cancer twice, was pursuing a career as a chef and had a child on the way when he was fatally punched and stomped on the head during a bar fight.
The 33-year-old New Zealand man, who worked at Yongah Hill Detention Centre in Western Australia, was left in a coma after the attack at the Commercial Hotel in Northam in April last year and died three weeks later.
The man responsible was 24-year-old Hubert Benjamin Humes, who still claims he joined the fight to defend his cousin despite a jury rejecting his assertion and finding him guilty of manslaughter.
Humes was sentenced in the WA Supreme Court on Wednesday to nine years in prison and must serve a minimum of seven years behind bars before he can be eligible for parole.
Justice Bruno Fiannaca said the victim was vulnerable and unable to protect himself from the punch.
"Your attack on him was cowardly," he said.
Justice Fiannaca accepted there was some degree of remorse and empathy, but it was obscured because Humes sought to justify his conduct.
It wa not the first time Humes has had a brush with the law for violent behaviour.
Humes was warned by a judge about his behaviour when he was handed a suspended prison sentence in May 2012 for twice punching a man and causing him grievous bodily harm.
Justice Fiannaca said Humes' attack on Mr Beaumont suggested he had not learned his lesson, so personal deterrence was an important factor in sentencing.
He noted Humes was a moderate risk of reoffending if he could not control his behaviour.
In a victim impact statement previously read to the court, Luke Beaumont said his brother had a heart of gold and had his life brutally taken.
"Our family has been cruelly ripped apart," he said.
Luke said his happy childhood memories were now sad and future happy times would be overshadowed by his brother's death.
Mr Beaumont's sister, Eliza, described the victim as her best friend.
"Living without him is unbearable," she said.
Justice Fiannaca described the family statements as eloquent and moving, noting their horror and emptiness.
"It will be with them forever," he said.
Mr Beaumont's parents followed proceedings via a link in New Zealand while Humes had many supporters in court.