Three weeks ago doctors began slowly easing back on the anaesthetic keeping him under in a bid to bring him round and, hopefully, see signs of life.
His daughter Gina-Maria, 17, son Mick, 14, brother Ralf and father Rolf spent eight hours on Sunday with Corinna at his bedside, talking to him in the faint hope that some of what they said would get through to him.
Experts say that the barbiturates and other powerful narcotics that have been keeping him under should now have left his body entirely.
The fact that he has not woken up only serves to fuel fears that he mad by left in a permanent vegetative state for the rest of his life.
'But must they separate in this situation from the Formula 1 legend?
It is a balancing act: On the one hand, the sponsors must pursue economic objectives, which point towards for a parting.
Corinna Schumacher spent the saddest birthday of her life on Sunday sitting at the bedside of her stricken husband with her children, her brother-in-law and her father-in-law speaking words of love and encouragement in a bid to rouse him from his coma.
Corinna turned 45 on Sunday with - as Austrian news website Format put it - "recovery for Michael Schumacher seeming all the more improbable." Medical experts around the world have reached the same opinion - including a former F1 doctor. It's a sad birthday, because the state of health of her husband, the formula 1 record World Champion Michael Schumacher, gives little cause for hope," it added.
"Nine weeks after the skiing accident of her husband it is emerging ever more clearly that he will not completely recover from his traumatic brain injury.
Medically this would border on a miracle - something that Corinna wished for on her birthday." Doctors now believe it will indeed be a miracle if Schumacher will ever again be the personality he once was.
On Monday Schumacher entered his 65th day in the coma in which he was placed on December 29 last year following a low-speed ski-accident at the French Alpine resort of Meribel.
He hit his head on a rock and suffered such severe brain injuries, he was not expected to last the night when he was flown in an emergency helicopter to Grenoble's University Hospital.