Van der Sar given indefinate leave
Annemarie van Kesteren, 36, collapsed at their home in the Netherlands two days before Christmas and has suffered a brain haemorrhage and a suspected stroke.
Ferguson, preparing for Wednesday's Premier League match against Wigan Athletic, said he had given the goalkeeper time off to look after his wife and their two children.
"Annemarie had a problem over in Holland a week ago and has been admitted to hospital," Ferguson told reporters on Tuesday.
"That is the best place for her to be. They have examined her twice and are trying to get to the root of it."
Van der Sar, 39, was in the Netherlands for treatment on the knee injury that has kept him out of the side since November 21.
"I have told Edwin to stay over there," Ferguson said. "There is no point in him being here. The best thing is for him to be with his wife. Hopefully, she will make a good recovery."