George HW Bush's chief of staff said the former US president is getting excellent medical treatment in Houston and that he would ask that people "put the harps back in the closet".
But Mr Bush's long-time Houston chief of staff Jean Becker said the 88-year-old is sick and is likely to remain in hospital for a while after a "terrible case of bronchitis which then triggered a series of complications".
She also urged people to keep him and his family in prayers.
Mr Bush has been in intensive care since Sunday. He was admitted to Methodist Hospital on November 23.