Sully was sent to Bush by America's VetDogs, an organization that trains and places service dogs with disabled military veterans and first responders.
Former President George H.W. Bush will be laid to rest wearing a pair of his trademark colorful socks.
A photo of Sully lying forlornly next to the president's casket at a Houston funeral home first went viral on Sunday, adding to his already large following on social media stemming from the past few months helping Bush as his health continued to fail.
George H.W. Bush's burial is set for Thursday at the Bush Library Center.
After helping Bush around the house with tasks like opening doors, summoning assistance and picking up dropped items, Sully will now have a new mission.
Sully is named after former airline pilot Chesley B. Former presidents or prominent politicians customarily lie in state. His service dog, Sully, will be accompanying the former president, CNN reports. On that day in June, he wore a pair with Clinton's face on them.
Mr. Bush was a decorated World War II fighter pilot who dedicated his life to public service as a congressman, ambassador, Central Intelligence Agency director, vice president and the 41st president, but the AP's tweet focused on his defeats.
Once Bush lies in state, his casket will be transported by motorcade on Wednesday morning to the National Cathedral, where a state funeral will be held. Sully's Instagram page showed the same photo.
Sully was 2-years-old when he was placed with the president, and "specifically matched to provide support and companionship to Mr".