Most poignantly, Michael's own son Mick, who was at his father's side aged 14 when he hit that rock and suffered a brain haemorrhage, is the F3 champion and has signed to race for Prema in Formula Two, F1's feeder series, next season. His future is promising, with seats at Mercedes or Ferrari a possibility one day.
Mick, who is said to be as private as his father, never delivers medical bulletins to outsiders, but last month he told Germany's RTL channel of his relationship with Michael before the accident.
"My dad asked if I wanted to do racing professionally or whether we should just do it for fun, as a hobby. I, of course, said I wanted to do it professionally.
"I always want to compare myself to the best, and my father is the best. He's also my idol. I'm pleased if I can compare myself to him. Many world champions compare themselves to my father. Even on days when the karting track was closed we'd go there and we were allowed to do some laps. That was always the best time."
But, in contrast to his son's fast-evolving career, Schumacher's progress has, at best, been slow.
However, Sportsmail understands that he is not bed-ridden. Nor is he existing on tubes. Yet it is believed he is receiving extensive nursing and therapy care, which has been estimated to cost more than £50,000 a week.
He is, it can be revealed, living with his close family in the main body of his house rather than in an outbuilding that some reports suggested had been constructed in response to his injuries as a special medical facility, a sort of hospital at home. In fact, the building work began before the accident occurred and the new cottage was always intended as a base for his widower father when he stayed.
Apart from one comment in 2016 from Schumacher's German lawyer, Felix Damm, confirming to a Hamburg court that the champion driver could 'not walk', further genuine updates have been hard to come by.
One leak was thwarted, with tragic consequences, in 2014. It came after Schumacher was transported from University of Grenoble Hospital, where he had two life-saving operations and remained for five months before coming out of his induced coma, to the University Hospital in Lausanne.
Some of his medical records were stolen and offered to media outlets for £40,000. The suspected thief, who worked for Rega, the air rescue company that moved Schumacher, was arrested, only to be found hanged in his cell while awaiting interview.
"We are at a loss for words and deeply shocked," said Sabine Kehm, loyal spokeswoman for the Schumacher family, at the time.
The following year, a photograph taken at his home and smuggled out by a 'friend' was being hawked around for £1m, in what German prosecutors described as a 'violation of his personal range of life' and a breach of privacy. The image never surfaced.
But we were recently given a glimpse inside Schumacher's life, through the words of an archbishop who is a confidant to two popes. Dr Georg Ganswein, Prefect of the Pontifical Household of Pope Francis and secretary of the retired Pope, Benedict XVI, was asked by Schumacher's friend and former Ferrari team principal, now FIA president, Jean Todt, if he would visit Schumacher at home. He did so in 2016.
Speaking in the last few weeks to German newspaper Bild, Ganswein revealed: 'I first talked to Corinna Schumacher and her mother. Then a therapist brought Michael Schumacher into the living room. I introduced myself and told him that I'm a secret fan, that I often watched his races, and that I was fascinated by how someone can steer such a machine through any weather at such high speed.
"I greeted Michael and held his hands. They were warm. Some things words cannot transport, but a touch can. Holding the hand of a sick person is something deeply Christian that provides consolation and closeness. That was important to me."
Todt is a regular visitor, too, but is careful never to disclose Michael's condition. He confirmed, however, that they had watched last month's Brazilian Grand Prix together at Schumacher's house. "I have pictures of Michael in my offices and apartments," Todt has said often, sometimes close to tears. "He is like a son to me."
Another of Schumacher's old Ferrari team-mates, Rubens Barrichello, wanted to pay a visit, but was told: "It would not do him or me any good." He said: "So I have no news, but we must respect the wishes of the family."
But these insights are rare. Those close to Michael know precisely why Corinna, as is her right, asked for his confidentiality to be meticulously observed by friends.
As Schumacher's spokesman Kehm says: "Michael always drew a clear distinction between his professional and personal lives, even during the most successful times of his career, and the family wants to honour that distinction now."
Moreover, pre-accident Schumacher possessed a sense of his own sporting prowess, of his athleticism, which he worked more professionally in the gym to cultivate than any racer before. He was a proud man, and nobody close to him now wishes his self-image, and that shared by his devoted fans, to be shattered by unpalatable updates.
So what next?
The German magazine Bravo have reported that medics are preparing in the utmost secrecy for Schumacher's transfer to a clinic in Dallas, Texas, specialising in the treatment of brain injuries.
Mark Weeks, the director, told the magazine cryptically: "We have a lot of experience with patients who are suffering this kind of trauma. There is probably no clinic in Europe that treats as many cases as we do."
The Schumacher family will not comment on the speculation.
But before any possible move there comes Michael's 50th birthday on January 3. Bar a change of tack, or a happy transformation in his health, he will not be seen on the landmark day except by his closest friends and family.
His fans will curse the desperate irony that a man who lived his professional life so fast — and suffered only a single serious Formula One accident, breaking his leg at Silverstone in 1999 — could have hurt himself this grievously in such seemingly innocuous circumstances. He was a fine skier and regularly won the downhill competition at the annual Ferrari winter retreat at Madonna di Campiglio in the Italian Dolomites, where he would knock back Bacardi and Coke in celebration.
And what a further cruel irony that Schumacher should have been a prominent supporter of the ICM, a brain and spine institute in Paris, long before his own calamity, working energetically for the cause. The president of ICM is family friend Professor Gerard Saillant, the world-renowned neurologist who flew to Schumacher's bedside to help save his life on that fateful day nearly five years ago.
Schumacher, though, never craved sympathy. As he said in 2007: "I've always believed that you should never ever give up, and you should always keep fighting even when there's only the slightest chance."
That sentiment gave rise to the "Keep Fighting Initiative", set up by spokeswoman Kehm and intended to "spread the positive energy that supporters of Michael have expressed to him over the years", through good deeds, cultural and educational. Indeed, trackside fans across the world still wave banners offering their support for the stricken Schumacher, their hopes undimmed.
Plans will soon be revealed for public recognition of his half- century. But, before those ideas are made known, Kehm expressed this one heartfelt wish: "The best present for Michael and the family as he approaches his 50th birthday is for people to remember him as the best racer and record-breaker that he is."