Houston (CNN) – George H.W. Bush is singing with doctors and nurses in the Houston hospital where he's been a patient for more than a month, according to the most recent update from the former president's spokesman.
"President Bush remains in the intensive care unit at Methodist Hospital, where he continues to improve," Jim McGrath wrote Friday. "The President is alert and, as always, in good spirits - and his exchanges with doctors and nurses now include singing. The Bushes thank everyone for their prayers and good wishes and, like their doctors, are cautiously optimistic that the current course of treatment will be effective."
On Thursday Bush's family expressed confidence Thursday that the 88-year-old former president would be released shortly from the hospital's intensive care unit, where he is being treated for an elevated fever.
McGrath said Bush was moved into the ICU so hospital personnel could more easily keep tabs on his condition, and that his family members were fully confident in the medical staff treating him.
The former president's most recent illness does not relate to his diagnosed Parkinsonism, McGrath said. On Wednesday, McGrath said Bush was in guarded condition and on a liquid diet. He added Thursday that the 41st president was being treated with Tylenol, among other things, but was in good spirits.
Doctors were initially treating Bush for bronchitis and a lingering cough. More recently he had been undergoing physical therapy in preparation for returning home, but developed a fever last week and began experiencing other complications that McGrath described as "a series of setbacks."
Bush was visited on Christmas by family members including his wife, Barbara, son Neil, daughter-in-law Maria and grandson Pierce. His daughter Doro visited Wednesday, and his son, former President George W. Bush, was making arrangements to visit as of Thursday. At 88, Bush is the oldest living former president, edging out Jimmy Carter by about four months.
Jean Becker, Bush's chief of staff, sent supporters a note on Thursday with reassurances that the former president's condition is not dire.
"Is he sick? Yes. Does he plan on going anywhere soon? No. He has every intention of staying put," Becker wrote. "He would ask me to tell you to please put the harps back in the closet."
Bush's healthcare in Houston is "unequaled anywhere" she wrote, asking supporters to "keep him and the family in your prayers.
"I am thinking heaven has not seen such a barrage of prayer intentions since 'It's a Wonderful Life,'" she wrote.
The George H.W. Bush years: Your take
Bush was first hospitalized from November 7 to 19, and then was readmitted to Houston Methodist Hospital on November 23. Bush and his wife live part of the year in Houston and spend summers at their compound in Kennebunkport, Maine.
In mid-December, his doctors expressed optimism he would be home for Christmas, but the fever and other complications have interfered with those plans.
- CNN's Miguel Marquez reported from Houston and CNN's Kevin Bohn reported from Washington