Sabine Kehm paid tribute to Michael Schumacher at the opening of an exhibition of his career, saying hopefully "one day" he will be back.
The seven-time World Champion suffered a serious head injury more than two years ago in a skiing accident in the French Alps.
He spent months in an induced coma at a Grenoble hospital before being moved to a rehabilitation clinic.
Schumacher returned home in September 2014 and since then his family have kept quiet about his condition.
There have, however, been reports from others with former Ferrari president Luca di Montezemolo recently stating that news about the 45-year-old is "not as good as one would have hoped."
And although Kehm did not reveal anything about Schumacher during the opening of the exhibition in Marburg, AAP reports her as having said: "Of course, we miss Michael on days like these.
"Unfortunately we cannot change what has happened."
She added that one can only hope that "he will one day be back again."