Ex-miner Tommy Ward was found badly injured at his home in Salisbury Road in Maltby, Rotherham, on 1 October.
About Â£30,000 was thought to have been taken.
Mr Ward had 15 great-grandchildren. He died on Tuesday night in Rotherham Hospital where he had been receiving treatment since the attack.
He suffered a "significant neurological injury" in the raid.
South Yorkshire Police said a post-mortem examination would be carried out to determine the cause of Mr Ward's death.
A safety deposit box was taken in the break-in, and a similar one was found in the Kilnhurst area two weeks after the attack, police said.
Det Ch Insp Vicky Short said the police investigation was ongoing, and appealed for witnesses to the attack.
She said: "Officers would still like to speak to witnesses, or anyone who has information about what happened.
"I urge anyone who has even the slightest piece of information to come forward and tell us what you know."
Two 19-year-old men previously arrested on suspicion of attempted murder and burglary have been released with no further action.
A teenage boy arrested on suspicion of handling stolen goods, and a 23-year-old man arrested on suspicion of attempted murder have also been released without further action.
After the raid, Mr Ward's daughter Jackie Perry, 52, described his attackers as "animals" and said they had "no conscience".
"They've walked away and shut that door knowing how seriously ill my dad was and they left him for dead, for the sake of money," she said.
South Yorkshire Police released a graphic picture, showing some of the injuries suffered by the great-grandfather, as part of their appeal.
An 80-year-old man who was severely beaten by robbers in his home has died five months after the attack, South Yorkshire Police have said.