While Bush remained in intensive care at Methodist Hospital in Houston, family spokesman Jim McGrath said in a statement the 88-year-old former president was on the mend, Politico and The Washington Post reported.
"The president is alert and, as always, in good spirits -- and his exchanges with doctors and nurses now include singing," McGrath said.
Bush's family said earlier they were confident he would be discharged but McGrath said they were not in a rush to get him home. He said Bush being treated for an elevated temperature and family members had confidence in the medical staff treating him, CNN reported.
Bush had been transferred to intensive care Sunday and his condition had been characterized Wednesday as guarded. He was on a liquid diet.
Bush chief of staff Jean Becker sent this upbeat email Thursday:
"Is he sick? Yes. Does he plan on going anywhere soon? No. He has every intention of staying put. He would ask me to tell you to please put the harps back in the closet."
Bush was diagnosed in February with lower body Parkinsonism, a condition that causes instability from the waist down, causing him to use a wheelchair. He was admitted to the hospital Nov.7 for a bronchitis-like cough and was discharged Nov. 19. He was readmitted Nov. 23.