His family have revealed that the 74-year-old has been living with the condition since 2015, with his wife Bonnie saying that she has seen her husband’s condition deteriorate since his diagnosis.
And former striker Ernie Moss died earlier this year at the age of 71 after a lengthy battle with dementia.
Kinnear came to Rovers as assistant to Dave Mackay in 1987 and briefly took over as boss following Mackay’s departure but was later replaced by Billy Bremner.
The former Wimbledon and Newcastle manager spent more than a decade as a player, notably winning the FA Cup, two League Cups and the Uefa Cup during his time with Tottenham between 1966 and 1975.
Kinnear’s wife Bonnie has confirmed her husband, who was forced to retire at the age of 30, was diagnosed with early onset vascular dementia in 2015 and his condition has since deteriorated.
In an interview with the Daily Telegraph, she said: “He started to get moody – a bit depressed. I thought, ‘This isn’t right.’
“Then he got aggressive in certain situations. It just wasn’t Joe. It was a problem trying to get him to see somebody but we eventually got him to a doctor and he was diagnosed in 2015.
“They classed it as early onset vascular dementia and, since then, he has just deteriorated. He’s in the late stage. It is heartbreaking to see how someone can change.
“He was larger than life. He loved people. He’d walk in a pub, buy everyone a drink, tell funny stories and be the life and soul of the party.”
After Kinnear retired as a player, he turned his hand to management and enjoyed plenty of highs with Wimbledon before spells with Luton, Nottingham Forest and Newcastle, while his last role was in 2014 as director of football at St James’ Park.
World Cup winners Nobby Stiles, Jack Charlton, Ray Wilson and Martin Peters have died after suffering from dementia while Sir Bobby Charlton Denis Law, Terry McDermott and Gordon McQueen are all living with degenerative neurological conditions.