Leith-raised Buchanan became the undisputed lightweight world champion in 1971 – and he is considered by many to be Scotland’s greatest ever boxer.
A statement released by son Mark Buchanan revealed his father “has good days and bad days” in his care home but hopes the 76-year-old will be at the statue ceremony in the Capital in August.
The statement read: “Further to some newspaper reports in September 2021, I report that my father Ken Buchanan MBE has a formal diagnosis of dementia.
“My father resides in a private care home in Edinburgh, where he is being well looked after.
“There has been a number of sporting stars of late announcing their dementia and at the age of 76 my father’s dementia has likely come similarly as a result of his sport.
“The result of my father’s dementia leaves him at times of being very forgetful.
“My father has good days and bad days as those who are familiar with dementia will know.
“I and my father’s Attorney had to make the difficult decision to place my father in a private care home for his own safety due to his increasing vulnerability.
“My father’s care is excellent and he enjoys visits from family and friends.
“Unfortunately we have had to take the difficult decision to stop certain people who were having a negative impact on my father visiting the private care home, this was not an easy decision, however my father’s wellbeing is of the utmost importance to us.
“My father’s fame lives on throughout the boxing world. We received on behalf of my father an invitation for him to be inducted into the West Coast USA Boxing Hall of Fame. Due to his cognitive impairment, we have had to turn down this invitation.
“It is likely that my father’s public appearances will now be limited. We are forever hopeful that my father will be able to attend the unveiling of his statute likely to be in August 2022.
“My father’s legacy has been passed on to many great Scottish boxers since the 1970s and I hope my father’s World Championship wins in the USA will continue to inspire young Scottish boxers to be great champions.”
Buchanan has been inducted into the International Boxing Hall of Fame.
Last year, in a documentary of his remarkable career, he said he has lived a "great life".
In "Undisputed: The Life and Times of Ken Buchanan", orginally shown on BBC Scotland, the ring legend studies old photographs from his life and career.
He recalls proud moments, from teaching playground bullies a lesson to the "magic" of representing Scotland, as well as the great tragedies of his life including the death of his most passionate supporter, his mother Cathy at the age of just 51, and the sickening low blow from ring legend Roberto Duran that cost him his world title.
He said: "I've had my life and I've had a good kick of the ball, and I've no axes to grind, none whatsoever. I've just lived my life and that's it because if I were to sit and worry about it I would never get any sleep.
"I'm just Kenny Buchanan, I was a world champion but that's all behind me, finished and done with."
He adds: "I think I'm a Jock Tamson, I don't put myself above nobody. Everybody is on the same level as me and I'm not feeling bad about my life and how it's went.
"I've had a good life – I've had a great life – I've done things that nobody in this country has done and I enjoyed it."
Buchanan took up boxing at eight years old, after persuading his dad Tommy to take him to Edinburgh's Sparta Club, and won his first medal aged eight and a half and weighing 3st 2lb. He made his international debut aged 17 and turned pro' after winning the British amateur title two years later in 1965.
He said: "I got bullied a wee bit at school because I was skinny. I had a wee bit of a chip on my shoulder but only because guys wanted to fight me, and then his brother would want to fight me because I would knock him out.
"It was just a left jab I gave him, and that was it. All I wanted to be was the champion of the world – the best fighter in the world."