In honor of Memorial Day on Monday, Sully's Instagram posted a tribute to the 41st president, who served as a Navy pilot during World War II. The pic of the adorable pup was taken in front of Bush's name at the National World War II Memorial in Washington D.C.
"Each of the patriots whom we remember on this day was first a beloved son or daughter, a brother or sister, or a spouse, friend, and neighbor' -- George H.W. Bush." the caption quoted the former president before adding a personal message.
"Always thinking of my best friend and the bravest military in the world ?? who made the ultimate sacrifice while defending our country for our freedoms," the caption continued.
Sully was also on hand when Bush was laid in state at the U.S. Capitol Rotunda. The pup was escorted in by former Secretary of Homeland Security Tom Ridge, and dutifully watched as mourners paid their respects.
Sully came to live with Bush last June, following his wife Barbara's death in April. The pair quickly bonded, with the former president even buying socks in honor of his beloved companion.
Since Bush's death, Sully, who was provided to Bush through America's VetDogs, has gone on to join Walter Reed National Military Medical Center's Facility Dog Program, where he continues to serve veterans. He's also met his namesake, pilot Sully Sullenberger, and received the American Kennel Club's Paw of Courage award.