Former president George H.W. Bush is improving and has been moved out of intensive care, a family spokesman said Saturday. 

"President Bush's condition has improved, so he has been moved today from the intensive care unit to a regular patient room at The Methodist Hospital to continue his recovery," Jim McGrath said in a statement. "The Bushes thank everyone for their prayers and good wishes."

The 88-year-old has been in and out of Houston's Methodist Hospital since early November, battling a severe cough. Doctors expected he would be able to go home for Christmas. Bush developed a rising fever that forced him last Sunday into intensive care. 

"President Bush remains in the intensive care unit at Methodist Hospital, where he continues to improve. The President is alert and, as always, in good spirits -- and his exchanges with doctors and nurses now include singing," spokesman Jim McGrath said. "The Bushes ... like their doctors, are cautiously optimistic that the current course of treatment will be effective."

Bush's chief of staff, Jean Becker, told family and friends in an e-mail obtained by CBS News that Bush  "would ask me to tell you to please put the harps back in the closet." The former president "has every intention of staying put," she added. 

Bush served in the presidency from 1989 to 1993. The oldest living former president, he marked his 85th birthday in 2009 by skydiving and was hoping to do the same for his 90th. However, he has developed a form of Parkinson's disease that limits his mobility.