Jules Bianchi "will be very heavily disabled" if he ever emerges from his coma, according to the former F1 driver Philippe Streiff.
The Frenchman, who was paralysed after a 1989 crash, caused a stir on Wednesday when he told French radio Europe 1 that his friend Michael Schumacher is paralysed, can't speak and has memory problems.
He did say, however, that Schumacher can "apparently communicate with his eyes to his wife and his manager".
The fiercely-private Schumacher camp, however, has played down Streiff's claims.
Unfortunately, I have no good news.
Manager Sabine Kehm told the Telegraph that the comments were just "his opinions" as Streiff "did not have contact with us".
But Streiff on Wednesday also commented on the injuries sustained by Marussia driver Bianchi in Japan seven weeks ago, saying the situation is "in my opinion worse for Bianchi than it is for Schumacher".
"Unfortunately, I have no good news," he said. "He is still in a coma and I do not think he will come out of it soon.
This was no fall onto a rock, which for Schumacher was already very serious. For Jules Bianchi it is very, very serious.
"If he does, he will be very heavily disabled. This was no fall onto a rock, which for Schumacher was already very serious. For Jules Bianchi it is very, very serious.
"I'm afraid, if he does come out of the coma, it will be very difficult for him, for the family," Streiff added.