President-elect Donald J. Trump has selected Mr. Boulos, the businessman and father-in-law of Mr. Trump’s daughter, as a senior adviser on Arab and Middle Eastern affairs.

Massad Boulus is the father of Michael Boulos, who married Tiffany Trump in November 2022 at Mar-a-Lago after they got engaged at the White House during Trump’s first term. They met on the Greek island of Mykonos at a club owned by actor Lindsay Lohan, People magazine reported in 2022.

Boulos is a friend of Suleiman Frangieh, a Christian ally of Hezbollah and its candidate for Lebanon's presidency. He is also in touch with the Lebanese Forces Party, a vehemently anti-Hezbollah Christian faction, the sources say, and has ties to independent lawmakers.