Fans of Formula One legend Michael Schumacher on Friday prepared to hold a silent vigil for his 45th birthday as he lay in a coma at a French hospital after a weekend skiing accident.

Ferrari, which is bussing in fans from Italy to the hospital in the southeastern French city of Grenoble, put out a message on its website saying “Forza Michael”, Italian for “go Michael”.

“He is tackling the most important fight of his life and therefore we want to send him very special wishes,” Ferrari said, as similar messages poured in from around the world.

German tennis ace Boris Becker wished Schumacher a happy birthday on Twitter, adding “Fight Schumi” in a German hashtag.

The retired seven-time motor sport world champion slammed his head against a rock on Sunday while skiing in the French Alps and has had two operations to remove bleeding and pressure on his brain. He is in an induced coma.

Schumacher’s family is at his side, including his wife Corrina, his two teenage children, his father Rolf and brother Ralph, also a racing driver.

“Following Michael’s skiing accident, we would like to thank the people from all around the world who have expressed their sympathy and sent their best wishes for his recovery,” the family said in a statement.

“We all know he is a fighter and will not give up.”

The Ferrari tribute created controversy, with some accusing the Italian firm – which asked fans to sport red, its colour, and its insignia – of exceeding the limits of good taste.

The Italian car maker has provided about 20 coaches across Italy to bus in fans for the silent tribute.

But not everyone was pleased. Roberto Luongo, the president of the Roma-Colesseo Ferrari club, said he did not want to be associated with any event linked to “a man who is suffering”.

“It’s very delicate and if I was among those who are close to Michael, such an initiative would not have pleased me,” he said.

Schumacher’s fan club in his childhood town of Kerpen said any celebration of the birthday would be in bad taste.

There have been conflicting statements about the speed Schumacher was going at the time of his accident at the Meribel ski resort, where he has a property.

The impact split the helmet he was wearing in two, according to a source close to the investigation.

The hospital has been faced with intense media pressure due to the frenzied interest. A vacant lot nearby has been turned into an impromptu parking area for television satellite vans.

Questions have emerged over exactly how the accident happened on a small, seemingly innocuous off-piste section of Meribel located between two ski slopes – one classed as easy and the other as intermediate.

Prosecutors are looking at whether the limits of the pistes next to the area where the accident happened were correctly marked, and whether the safety releases on Schumacher’s skis operated properly.

Prosecutors were not expected to make any statement on the investigation until early next week.