The late president's son George W. Bush marked the holiday with a bike ride to honor fallen service members

By Ashley Boucher and PEOPLE
George W. Bush dog Sully
Credit: Sully HW Bush/Instagram

George H. W. Bush‘s former service dog, Sully, posed for a photo to pay tribute to the 41st president of the United States on Memorial Day.

"Always thinking of my best friend & the bravest military in the world who made the ultimate sacrifice while defending our country for our freedoms," the photo's caption on Instagram reads, along with a quote from Sully's late best friend: "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."

The yellow Labrador retriever sat next to the National World War II Memorial in Washington, D. C., for the shot.

Bush had earned the Distinguished Flying Cross for his service as a U.S. Navy pilot in the war.

Sully joined Bush in the last months of his life as his service dog, provided by non-profit America's Vet's Dogs.

"A great joy to welcome home the newest member of our family, "Sully," a beautiful — and beautifully trained — lab from @AmericasVetDogs. Could not be more grateful, especially for their commitment to our veterans," the former president shared on Twitter last June. Sully stayed by his side until the very end, even laying by Bush's casket after he passed away in November.

Sully, who was awarded the Paw of Courage award by the American Kennel Club in March for his dedication to the former president, now provides comfort to veterans at the Facility Dog Program at Walter Reed National Medical Center in Bethesda, Maryland.

H. W. Bush's son, George W. Bush, also marked the holiday by remembering those who gave their lives in service, participating in a Memorial Day bicycle ride.

The 43rd president shared a photo of the cycling group on his Instagram, captioning the photo, "Enjoyed a great ride honoring the fallen this morning with fellow grateful citizens, veterans, and first responders."

George W. gave a eulogy at his father's December service, remembering his sense of humor and words of wisdom throughout the years.

"He loved to laugh, especially at himself. He could tease and needle, but never out of malice. He placed great value on a good joke," he said, adding that the elder Bush taught his kids "never to be defined by failure."

WATCH: The Emotional Moment Jeb and George Bush Shared After 43's Heartfelt Eulogy

Bush "taught us what it means to be a wonderful father, grandfather, and great-grandfather. He was firm in his principles and supportive as we began to seek our own ways," George W continued. "He encouraged and comforted, but never steered. We tested his patience — I know I did — but he always responded with the great gift of unconditional love."

This story originally appeard on PEOPLE