Former President George H.W. Bush continues to improve and his “exchanges with doctors and nurses now include singing,” a family spokesman said Friday afternoon.
“The president is alert, and as always, in good spirits,” Jim McGrath said.
He added that while the 88-year-old former president still remains in the intensive care unit at Methodist Hospital in Houston, physicians are "cautiously optimistic that the current course of treatment will be effective.”
Bush has been hospitalized since Nov. 23. He was moved into intensive care on Sunday for treatment of a fever following a bronchitis-related cough.
Jean Becker, Bush's chief of staff, earlier told family and friends in an email that the former president "would ask me to tell you to please put the harps back in the closet."
Bush is the oldest living U.S. president. He famously skydived on at least three of his birthdays after leaving office – most recently when he turned 85. In recent years though a form of Parkinson’s disease forced him to use a motorized scooter or a wheelchair to get around.
The Associated Press contributed to this report.