Derek Robertson was ambushed in his own home in Maybole, Ayrshire by a machete-wielding robber and his female accomplice demanding the cash box.
The now 69-year-old was repeatedly struck with the weapon as he desperately tried to defend himself.
The attack on December 11, 2019, came the same day his sister Greta Robertson, 64, reported him to police for having the safe – containing almost £130,000 – in his home.
This was despite there initially being an agreement between the pair and two other siblings that Derek should keep hold of it while Hamilton was in hospital.
But, Greta – one of the people who had power of attorney for their dad’s personal affairs – had demanded it be returned.
Jurors heard how they had been a “close family”, but that this dispute shattered relations.
Detectives probing the attack ended up arresting HGV driver Barry Marshall – the partner of Greta’s daughter.
Marshall’s friend Marion Hawkins was also held.
The pair – both 41 – denied being the culprits during a trial at the High Court in Glasgow.
Among the claims Marshall made to police was that he had been in the area of Derek’s home because he was having an affair with another woman.
Hawkins said she had been in Marshall’s BMW X5 that day after he suggested going for a “run” in it to Ayrshire in the middle of winter.
Both incriminated a man said to be a local criminal.
Greta – who was not on trial – denied “encouraging” anyone to target her brother and insisted she was “horrified” when she learned Derek had been stabbed.
Marshall and Hawkins are now behind bars after they were each convicted of attempted murder and the robbery of Derek’s mobile phone.
They will be sentenced next month.
Jurors were told how Hamilton – known as Milton – had ended up in hospital in 2019.
A pact was said to have then been made by the Roberston siblings that Derek should keep the locked safe at his home rather than it staying in an empty house.
Great told the trial: “My brother felt it had to be removed. I did not know the safe was gone.
“I did not find out at the time, but it made sense.”
The trial heard, however, that there was then a “disagreement” when their dad got out of hospital.
Greta said she asked “several times” for the cash box to be returned.
Derek told the court his sister was “constantly ringing” him.
Greta stated her dad eventually “asked her to go to the police”.
The view of Greta and her daughter Jade was that Hamilton’s safe was “rightfully his”.
On the day of the attack, Derek had been home ill with what he now suspects was Covid.
He was on the phone to his other sister Lorna when his doorbell was repeatedly rung.
She had urged Derek not to answer, but he eventually did.
As he opened the door, he was “knocked back” by a gloved woman before “a guy jumped in with a big machete”.
The court heard the armed thug started “chopping” at Derek across his body with the deadly weapon.
Derek recalled: “If I had not raised my arm, I do not think I would still be here.”
He told prosecutor John Macpherson there were yells of “where is the safe, where is the money?”.
Derek – wearing just a dressing gown and boxer shorts – tried unsuccessfully to escape into the kitchen and shut the door.
The witness: “He still kept trying to get me. Whenever he got closer, he had another shot.
“He actually climbed over the table at one point to get at me.”
The female then realised the call to Lorna was still connected and the mobile was snatched.
As the machete thug continued to chase Derek, his accomplice was heard telling him: “Enough Barry, enough Barry.”
Derek told jurors: “For some reason, they decided they were going and said: ‘We will be back. It is not finished’.”
Derek tried to call his sister back on his landline, but his injuries were such that he could not hold the phone. He eventually went to his neighbour to raise the alarm.
He has been left scarred for life as a result of his ordeal.
Greta said she learned that night what had happened to Derek.
She told the trial: “I was horrified. I could not understand.”
Asked if she had any involvement or put anyone up to it, Greta stated: “No, never. I only wanted my dad to get his money back. We had been a close family.”
She added “the whole relationship dissolved” with the others.
In his evidence, Marshall, of Pollok, Glasgow, admitted giving police “a pack of lies” including the story of the bogus affair.
He insisted the truth was Hawkins – who he had known on-off since they were teenagers – had offered to be a go-between with the Robertsons to resolve the safe dispute.
Hawkins, of East Kilbride, Lanarkshire, was a stranger to the family.
But Marshall said: “I did not think it was a bad idea.”
He said they went to Derek’s on the day of the crime, but he sat in his private-reg 4×4 while Hawkins went in. Marshall denied being part of any attack.
Hawkins – now in a wheelchair due to health issues – also refuted the accusations stating she had “no reason” to be in Derek’s home.
Lady Poole deferred sentencing for reports.
The judge told the pair: “This attack was carried out on a man in his 60s in his own home.
“This was a despicable thing to do. The victim impact statement I have read speaks of the physical and emotional impact on him.”
