Chip Somodevilla/Getty From left: Robert Trump hugs his brother Donald Trump after the president delivered his acceptance speech in the early morning hours of Nov. 9, 2016, in New York City
“I have a wonderful brother," the president, 74, said. "We’ve had a great relationship for a long time, from day one — that’s a long time. He’s in the hospital right now and hopefully he’ll be alright. He’s having a hard time.”
The president did not elaborate on what caused Robert to be taken to the hospital.
ABC News, who first reported Robert's hospitalization, cited multiple sources describing the 72-year-old as "very ill."
The White House confirmed with PEOPLE that Trump plans to visit his brother at the Manhattan hospital later on Friday. (White House aides did not respond on the record to further questions about Robert's health.)
Diane Bondaress/AP/Shutterstock Robert Trump (left) and his older brother, Donald Trump together in 1999
Robert has largely remained out of the public limelight since retiring from the family's real estate business.
He told Page Six in 2016 that he was “gainfully retired" and then living on Long Island, while the BBC reported in 2018 that the president's brother was "said not to court publicity and prefers a quieter life."
Related: Donald Trump's niece set to publish 'harrowing and salacious' tell-all
Robert was on hand to celebrate his brother Donald's 2016 election win, hugging him after the newly elected president delivered his acceptance speech at the New York Hilton Midtown in New York City.
Trump's brother resurfaced in the media this summer when he filed a lawsuit against their niece Mary after she announced plans to release a tell-all memoir about the president's family.
Mary is the daughter of Fred Trump Jr., Robert and Donald's oldest brother, who died in 1981 at the age of 42 following years of alcoholism.
Sonia Moskowitz/Getty From left: Donald Trump, Ivana Trump, Robert Trump and Blaine Trump at the Rainbow Room in New York City
Citing a 2001 non-disclosure agreement between the family members, signed in a settlement over patriarch Fred Trump Sr.'s financial estate, Robert unsuccessfully argued in court that Mary was breaching the terms of the family's agreement by publishing her memoir.
Robert had called Mary's book — Too Much and Never Enough — a "disgrace" and said the tell-all was filled with sensationalized mischaracterizations of the family's affairs.
However, the court ultimately sided with Mary, and her best-selling book hit shelves in mid-July.
"I and the rest of my entire family are so proud of my wonderful brother, the president, and feel that Mary’s actions are truly a disgrace,” Robert told The New York Times in June.
Robert was previously married to former wife Blaine for 25 years before they got divorced in 2008.
Trump also has two older sisters, retired U.S. appeals court judge Maryanne Trump Barry, 83, and banking executive Elizabeth Trump Grau, 78.