Dennis Taylor, aged 82, survived being attacked by Amos Wilsher, 29, and his brother Jason, 22, who ransacked his home in 2017.
The pair were today found guilty of wounding with intent and conspiracy to rob Mr Taylor.
Amos Wilsher was also found guilty of killing 88-year-old Josephine Kaye by a jury, which also convicted him and Jason Wilsher of the murder of Arthur Gumbley.
Mr Gumbley, 87, passed away three weeks after being callously beaten by the brothers, who stormed his property in November 2017.
The pair, formerly from Alfreton, burst into the retired company director's £700,000 bungalow in Little Aston, in the West Midlands, and repeatedly punched and kicked him as he lay helplessly on the ground.
He was also dragged across the floor suffering carpet burns to his back and had a watch forcibly pulled from his wrist, skinning the flesh from his hand.
Their victim, known as Bob, was found in a pool of blood and rushed to hospital where he was treated for severe bruising to his left eye, neck, chest, hands and right arm.
Police released shocking pictures of Mr Gumbley's injuries as he lay in his hospital bed before he passed away from his injuries three weeks later on December 12, 2017.
Amos Wilsher then acted alone when he viciously attacked Josephine Kaye, 88, at her home in Stoke-on-Trent, Staffs, in February 2020.
He posed as a gas firm worker to remove a padlock from a gate before killing Mrs Kaye and stealing her safe containing £20,000.
The OAP was thrown to the ground and threatened with a screwdriver.
She suffered a broken leg and significant bruising and later died of her injuries in hospital three weeks later on March 17.
Today Amos was found guilty of the murders of both Mr Gumbley and Mrs Kaye following a trial at Coventry Crown Court.
Brother Jason was found guilty of murdering Mr Gumbley after a jury of six men and six women spent five hours and 50 minutes deliberating.
The siblings were also found guilty of wounding with intent and conspiracy to rob after Mr Taylor was attacked.
Three masked men had knocked on his farmhouse door in Creswell, before he was repeatedly struck on a head, hit with a baseball bat and had a knife pushed through his lip.
The men ransacked his home before making off with jewellery and £800 in cash after demanding the code for his safe.
Following a four-month long study of CCTV detectives placed a blue Mazda RX8 in the area of the Mr Gumbley’s and Mr Taylor’s homes.
It was found burnt out and abandoned near to Tibshelf on November 25 2017 within roughly an hour of the robbery and assault of Mr Taylor.
Detectives found out it had been sold privately in London and telephone numbers involved in the sale led to Wilshers’ family members.
Detective Chief Inspector Dan Ison, of Staffordshire Police’s Major Investigations Department, said: “Amos and Jason Wilsher targeted elderly, vulnerable victims who lived alone. They ruthlessly and unnecessarily used violence which caused the deaths of 87-year-old Arthur Gumbley and 88-year-old Josephine Kaye.
"I would like to pay tribute to Dennis Taylor who survived an attack by the brothers and thank him for reliving the horrific ordeal he was subjected to which has been significant in helping secure their convictions.
“My thoughts remain with Arthur and Josephine’s families and I thank them for their support of the investigation.
"During the trial, they have had to listen to the detail of what happened and have conducted themselves with dignity throughout.
"No sentence will bring back the lives of Arthur and Josephine but I hope the convictions will provide closure knowing that justice has now been served."
Amos and Jason Wilsher will be sentenced at Coventry Crown Court at a later date.