George H.W. Bush and Wife Barbara Hospitalized

George W H bush Getty 2014 - H
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The 92-year-old former president wrote a letter to Trump explaining why he'll be missing his inauguration: "My doctor says if I sit outside in January, it likely will put me six feet under."

Former President George H.W. Bush and his wife, Barbara, remain hospitalized in Houston, where he was in intensive care for pneumonia and she was being watched after complaining of fatigue and coughing.

The 92-year-old former president went into the ICU on Wednesday and underwent a procedure "to protect and clear his airway that required sedation," family spokesman Jim McGrath said in a statement.

Bush was stable and resting comfortably at Houston Methodist Hospital, McGrath said.

The 41st president was placed in the ICU to address "an acute respiratory problem stemming from pneumonia," McGrath said. He later told The Associated Press that doctors were happy with how the procedure went. Bush was first admitted to the hospital Saturday for shortness of breath.

"I don't think there's a whole lot of money to be gained betting against George Bush," McGrath said. "We're just kind of in a wait-and-see mode."

McGrath said Barbara Bush, who is 91, had not been feeling well for a couple of weeks and decided "to take it out of committee and have the experts check it out." He described the move as precautionary.

Physicians initially believed the former president would be released later this week following several days of treatment, but his stay has been extended, McGrath said. There is no timetable for his release.

Doctors want to see how the former first lady responds to treatment before allowing her to return home, he said.

President Obama sent the Bushes his prayers during his final press conference on Wednesday and former president Bill Clinton took to Twitter to say, "41 and Barbara—thinking about you both and sending wishes for a speedy recovery. Love, 42." Hillary Clinton followed his tweet by saying, "Bill & I have you in our thoughts & look forward to you both being back on your feet soon, wild socks & all."

Bush's office announced earlier this month that he and Barbara, would not be attending Donald Trump's inauguration this week due to the former president's age and health.

In a newly published letter to Trump, Bush told the president-elect: "My doctor says if I sit outside in January, it likely will put me six feet under." Adding, "Same for Barbara. So I guess we're stuck in Texas."

He said the pair will be with Trump in spirit and wished him the "very best as you begin this incredible journey of leading our great country." He added, "If I can ever be of help, please let me know."

Trump later thanked Bush for his "wonderful letter" and tweeted that he was "looking forward to a speedy recovery" for the Bushes. 

Bush, who served as U.S. president from 1989 to 1993, has a form of Parkinson's disease and uses a motorized scooter or a wheelchair for mobility. He was hospitalized in Maine in 2015 after falling at his summer home and breaking a bone in his neck, and was hospitalized in Houston the previous December for about a week for shortness of breath. He spent Christmas 2012 in intensive care for a bronchitis-related cough and other issues.

The Bushes, who were married Jan. 6, 1945, have had the longest marriage of any presidential couple in American history. At the time of their wedding, he was a young naval aviator. She had been a student at Smith College.

After World War II, the pair moved to the Texas oil patch to seek their fortune and raise a family. It was there that George Bush began his political career, representing Houston for two terms in Congress in the late 1960s and early 1970s.

Despite the loss of mobility, Bush, father to former president George W. Bush and former Florida governor Jeb Bush, celebrated his 90th birthday by making a tandem parachute jump in Kennebunkport, Maine. Last summer, Bush led a group of 40 wounded warriors on a fishing trip at the helm of his speedboat, three days after his 92nd-birthday celebration.

George Herbert Walker Bush, born June 12, 1924, in Milton, Mass., also served as a congressman, CIA director and Ronald Reagan's vice president. Only one other U.S. president, John Adams, had a son who also became president.

Jan. 19, 8:50 a.m. ET: Updated with the Bushes' Thursday status.

Jan. 18, 12:50 a.m. ET: Updated with Bush letter to Trump.

1:35 p.m.: Updated with Bush and wife Barbara's status.