A groom-to-be says he stabbed his brother in the back while being held in a headlock, unable to breathe from being strangled, after a night of drunken arguments.
Bernard John Robbins is on trial in a Brisbane court charged with murdering Gregory Robbins, 61, at a home in Buderim on the Sunshine Coast in 2019.
Three days later Bernard Robbins was due to get married.
His brother had arrived from Perth on June 12 to attend the wedding.
That same day - after "general chit-chatting" - an argument broke out between the men who were drinking on the patio of the unit the former chef shared with the woman he was due to marry.
Greg Robbins first "arced up" in response to a comment about mending the relationship with his daughter, the groom-to-be told the Brisbane Supreme Court on Friday.
In response Gregory Robbins referred to their mother as a "stunned mullet".
As the name-calling and swearing continued, Bernard Robbins told his brother several times to leave, while Gregory Robbins asked bride-to-be Sally Doring if she was "going to marry this c***".
The court heard earlier comments made by Ms Doring suggested the wedding may be in jeopardy because of Bernard Robbins' behaviour.
Bernard Robbins told the court he was "pretty upset", putting his brother's bags on the driveway and telling him again to leave.
Trying to get "the final say" while his brother was near the suitcases, Bernard Robbins said he shouted, "F*** off back to Perth", adding he never wanted to see his brother again and saying he'd had enough.
Gregory Robbins quickly walked towards his brother in the garage before throwing the first punch, the court was told.
A "flurry of punches" followed with Bernard Robbins also getting in a couple before he found himself in a headlock and petrified, he said.
"I tried to yell out, to say, 'I can't breathe', all I could manage was a couple of gasping, grunting noises, that was it," he added.
Bernard Robbins said he grabbed a knife - which was on a massage table from cutting boxes because they had moved house weeks earlier - and stabbed his brother twice in the back, forcing him to release his hold.
He used a reasonable amount of force, thinking, "If I don't get him to let go I am going to get seriously hurt or he'll kill me," the 59-year-old said.
But Gregory Robbins again grabbed his sibling.
Bernard Robbins lashed out again with a knife.
He thought he'd stabbed his brother twice in the belly, but Gregory Robbins collapsed on the floor with four life-threatening stab wounds, eight to 12 centimetres deep, to his heart.
He died in hospital in the early hours next day.
"It was all quite surreal, just like a bad dream," the younger brother told the jury.
"I was in fear for my life when that happened."
Bernard Robbins denied he had his brother in a headlock while punching him, as the court heard earlier from Gregory Robbin's partner Karen Vanden Driesen.
Asked why he was yelling "f***ing c***" and kicking the walls of the police van after his arrest, Bernard Robbins said he was in shock and disbelief.
Asked what was going through his mind, he responded: "My brother's seriously injured, the girls are all hysterical, there's blood everywhere (and) we were supposed to be coming together for good times ... not for this to happen."
Police later estimated Bernard Robbins had a blood alcohol concentration (BAC) of 0.182 at the time of the stabbing, while his brother's BAC level was 0.217.
The trial continues before Chief Justice Catherine Holmes.