Ali: The greatest fighter of all is 65 this week. His family are worried that he won't see 66

Muhammad Ali will be 65 on Wednesday, and there are growing fears for his life. The health of the world's greatest sporting icon has deteriorated so rapidly in recent weeks that one of his closest friends said last night: "Although he will now qualify for Medicare he doesn't need it - what he needs is our prayers."

Gene Kilroy, also 65, who has known Ali for more than 40 years and was his business manager for most of the former world heavyweight champion's 61-fight professional career, added: "When I see him now I want to cry. He looks like he is wasting away and is getting frailer by the day."

Ali, who is deep in the grip of Parkinson's disease, cannot walk unassisted, can barely speak and shows little or no recognition of those around him.

His last public appearance was at a football match at the Orange Bowl in Miami on New Year's Day. "He looked terrible," says Mr Kilroy. "It makes me angry that they are still taking him all over the place when he should be at home resting."

Ali was also briefly at the ringside in Madison Square Garden, New York last month to watch his daughter, Laila, one of his nine children and now herself a world champion - apparently much to Ali's chagrin as he doesn't approve of women's boxing. He was driven to his front-row seat in a golf cart and observers say it was a pitiful sight as he sat blinking and twitching involuntarily as fans crowded around.

Distressingly, the famous Ali shuffle has long ceased to be a dazzling quickstep and is a painfully slow wobble. Yet Ali remains the most recognisable human being on earth, and still the best-loved, most charismatic sports figure of all time. The one and only true Lord of the Rings.

It is the cruellest irony that the greatest orator sport has known, the street poet of pugilism who floated like a butterfly and stung like a bee, has been reduced to a shambling shadow of his former self because of the nerve-paralysing condition from which his house painter father died - but one surely exacerbated by having 10 fights too many and absorbing terrible punishment in his Rumble in the Jungle with George Foreman and Thrilla in Manila with Joe Frazier. He memorably won both, but said the latter was "the closest thing to dyin'".

The last time Ali had a global audience was as a member of the New York contingent which bid unsuccessfully in Singapore for the 2012 Olympics. They took him along because of the impact he had made on three billion viewers when he lit the flame with a trembling hand in Atlanta in 1996. But it proved a dreadful mistake. Ali was mute and zombie-like, his movements robotic, his gaze blank. Many were in tears as he tried to rise to his feet to acknowledge the huge ovation, but fell off his chair.

As someone privileged to follow him around the world, from Atlanta to Zaire, from Madison Square Garden to Manila, it was heart-rending to watch.

He reigned in an age when boxing crowns were not bits of bling. He fought and beat everyone of note. No challenge was ever shirked from the moment he "shook up the world" in 1964 by defeating Sonny Liston, a seemingly indomitable ogre, and then announced he had converted to Islam.

Yet Ali always was a ladies' man and it has been the love of one good woman that has helped keep him alive. His 48-year-old fourth wife, Lonnie, has devoted her life to nursing him since they were married in 1986. A tall, striking woman, she accompanies him everywhere. Wherever he goes, Ali commands a fee of $100,000 (£51,000), and Lonnie controls the purse strings, ensuring nothing is squandered.

He is still able to live comfortably, and has the best medical help - he certainly doesn't need Medicare (the nearest US equivalent to the NHS, for which he will qualify at 65) - but Lonnie insists money is not the reason why he is kept in the spotlight. "This is not just his living, it is also his life. He simply couldn't bear to fade away," she says. She has known Ali since she was a five-year-old living opposite his family home in Louisville, Kentucky. She remembers him as Cassius Clay, coming home from training camp: "He had this great big bus, and he'd take us all over Louisville. He'd shout, 'Who's the greatest?' We'd all answer, 'You are!'"

They met up again in very different circumstances. He had been through a savage beating in his penultimate fight, against Larry Holmes in 1980. "I met him one day in Louisville and he stumbled getting out of the hotel lift. Something was obviously wrong. Then a friend told me he was sick and needed someone to take care of him, or he might die." So Lonnie flew to Los Angeles, where he then lived. "He needed someone by his side." He was diagnosed with Parkinson's in 1985 and they were married a year later. "There is a quality about Muhammad that makes you want to give him all the love in the world," she says.

They have an adopted son, Assam, 15, and live in their Michigan farmhouse, which used to be one of Al Capone's hideouts. But Lonnie has been househunting in Louisville, where the Muhammad Ali Center, an $80m shrine to his career, has been opened. Ali has intimated it is time to return to his roots for what, sadly, may be the final round.

The style of a champion, by Norman Mailer

"Clay punched with a greater variety of mixed intensities than anyone around, he played with punches, was tender with them, laid them on as delicately as you put a postage stamp on an envelope, then cracked them in like a riding crop across your face, stuck a cruel jab like a baseball bat ... next waltzed you in a clinch with a tender arm around your neck, winged away out of reach on flying legs, dug a hook ... a mocking soft flurry of pillows and gloves, a mean forearm, cutting you off from coming up on him, a cruel wrestling of your neck in a clinch, then elusive again, gloves snake-licking your face like a whip."

From 'Ego' by Norman Mailer, first published in 'Life' magazine March 1971