Bush's son, Neil, and his wife also visited on Tuesday, and one of Bush's grandsons was planning to stop by as well, said Jim McGrath, Bush's spokesman in Houston.
The 88-year-old has been in the hospital since Nov. 23 with a lingering, bronchitis-like cough. A hospital spokesman had said Bush was likely to be released to spend Christmas at home, but then McGrath said the former president developed a fever.
Doctors remain "cautiously optimistic" Bush will recover, but want to keep him in the hospital while they help him build up his strength and balance his medications, McGrath said.
On Christmas, the Bush family normally eats at Gigi's Asian Bistro in Houston's Galleria neighborhood, McGrath said. There were plans to pick up food at the upscale restaurant and bring the meal to the hospital.
Bush has been receiving visitors for weeks, including two by his son, former President George W. Bush, and one by Jeb Bush, former governor of Florida.
Bush and his wife reside in Houston during the winter, and spend their summers at a home in Kennebunkport, Maine.
The former president was a naval aviator in World War II -- at one point the youngest in the Navy -- and was shot down over the Pacific. He achieved notoriety in retirement for skydiving on at least three of his birthdays since leaving the White House in 1992.