The White House confirmed Friday that Robert Trump, the younger brother of President Trump, had been hospitalized in Manhattan and that the president would be visiting him later in the day.

It has not been confirmed what that younger Trump, 72, is being treated for, but officials did say that the illness is serious.

The youngest child of Fred Trump Sr. and Mary Anne MacLeod-Trump, Robert Trump was born in 1948 and is said to have a “very good relationship” with the president.

Robert Trump been a businessman and real estate developer and was at one point responsible for the Trump Organization’s real estate holdings outside of Manhattan. He is also the president of Trump Management, a business owned by the surviving Trump siblings, including older sisters Maryanne Trump-Barry and Elizabeth Trump-Grau.

Robert Trump is a member of the board of directors for ZeniMax Media, a video game company that owns Bethesda Softworks, publisher of popular series like Fallout, The Elder Scrolls, and Wolfenstein. He also invests in SHiRT LLC, a co-owner of the identity security firm, CertiPath.

He was  married to Blaine Trump from 1980 to -2008. He  married Ann Marie Pallan in March, according to reports.

Robert Trump was among the family members to file a lawsuit to prevent the publishing of a book written by his niece, Mary L. Trump – daughter of the late Fred Trump Jr. – “Too Much and Never Enough.”

The book purported to expose the toxic and emotionally abusive environment that the president was raised in. The family argued that the book violated a non-disclosure agreement that Mary Trump signed in order to receive a portion of her grandfather’s inheritance.