Transcript for Bush remembers his father: 'He listened and he consoled'

And we are in the nation's capital this evening after a truly moving day honoring the nation's 41st president. His son, president George W. Bush, breaking down, score come with emotion as he remembered his father, George Herbert walker bush. At Washington's national cathedral, all of the living presidents and first ladies gathered to pay tribute and to listen to a son remember his father, the 43rd president honoring the 41st. He shared his last conversation with his father, the day he died. And the nation watched as George W. Bush was overcome, his heartfelt words for his father. And moments ago, the plane landing in Houston, carrying former president bush home. Tonight, what brought a son to tears, and that rare sight when so many presidents and first ladies come together. Take a look. Just before 10:30 this morning, the casket carrying America's 41st president, George Herbert walker bush, brought down the steps of the U.S. Capitol after lying in state. A 21-gun salute. The bush family, their hands to their hearts, including the nation's 43rd president, George W. Bush. First lady Laura bush by his side. At the Washington national cathedral, all of the living U.S. Presidents and first ladies were gathering, for one of those rare moments when they all come together, a nation watching. Former first lady Michelle Obama hugging fellow first lady Hillary Clinton. Leaders and dignitaies there, too. Prince charge with general Colin Powell. The queen sent him, remembering her trip to Texas all those years ago. President bush's motorcade making its way to the cathedral. Passing in front of the white house. The route lined with well-wishers. Some in tears. Others holding their hearts. Back inside the cathedral, president trump and the first lady Melania trump arrived. The president shaking former president Obama's hand and Michelle Obama's, too, as she says good morning. Bill Clinton with a glance. But there was no interaction between the trumps and the Clintons. Hillary Clinton looking forward the entire time. And then the bushes arrive. First lady Laura bush taking president orge W. Bush's arm. President bush, greeting the former presidents and first ladies, shaking each one of their hands, beginning with the trumps. Handing something to Michelle Obama, after he gave her a cough drop at senator John McCain's funeral. It appeared today he had done it again. Then, greeting the Clintons. Bill Clinton so close to his father. And thanking the Carters for being there, too. Shortly after, the casket is carried in. There was silence in the cathedral as it passes by the bush family, sat down by eight military pallbearers. Family and friends spoke. And then, a son stood before that cathedral and the country, to honor his dad. George W. Bush walking to the podium. Tapping his father's casket on the way. Speaking of his father's humility. Like many of his generation, he never talked about his service until his time as a public figure forced his hand. The shootdown. We learned of the death of his crewmates, whom he thought about throughout his entire life. And we learned of the rescue. Reporter: Speaking of his father's kindness and the love he so often shared. Many a person would tell you that dad became a mentor and a father figure in their life. He listened and he consoled. He was their friend. And perhaps the unlikeliest of all, the man who defeated him, Bill Clinton. My siblings and I refer to the guys in this group as brothers from other mothers. Reporter: Talking about his father's boundless energy, speeding in his boat. The secret service trying to keep up. He was born with just two settings -- full throttle, then sleep. Reporter: He spoke of his father's character. We tested his patience, I know I did. But he always responded with the great gift of unconditional love. Reporter: And then he shared his final conversation with his father. Last Friday, when I was told he had minutes to live, I called him. The guy answered the phone, said, "I think he can hear you but he hasn't said anything for most of the day." I said "Dad, I love you and you've been a wonderful father." And the last words he would ever say on Earth were, "I love you, too." Reporter: He said his father was imperfect. Offering a tender list. In later years, watching police shows with the volume all the way up. Barbara at his side. In his old age, dad enjoyed watching police show reruns with the volume on high. All the while, holding mom's hand. After mom died, dad was strong, but all he really wanted to do was hold mom's hand again. Reporter: His father had said in his final days he hoped he would be reunited in heaven with his darling bar and their daughter, robin, who they lost to leukemia at 3 years old. And this is how his son finished -- A great and noble man, the best father a son or daughter could have. And in our grief, let us smile knowing that dad is hugging robin and holding mom's hand again. Reporter: Tapping his father's casket once more. Wiping his eyes. His brother Jeb reaches for his hand. A kiss for Laura bush. A son, honoring his father. It was incredibly moving today. The bush family leaving the national cathedral just as they arrived, all together. George and Laura bush leading the way. As they return to Texas to bury their father and grandfather next to Barbara Bush and the daughter they lost at 3, robin. As you saw there, one of the most remarkable images of this day, all of the living American presidents together, even in a divided time. I want to bring in ABC's Jonathan Karl tonight. It seems it might have been one last call to service for the late president, George H.W. Bush, orchestrating this rare moment of unity. Reporter: In fact, David, the bush namely reached out to the trump white house months ago. They had a clear message. The message was that president bush wanted president trump and the first lady to be part of his memorial. And if you looked out at that crowd today, you also noticed that the bush family also invited many of the president's top advisers, top white house officials were also there. And for his part, president trump honored every request that the bush family made in planning this week's events, and perhaps most importantly, he remained quiet, uncharacteristically so, leaving the spotlight for this week entirely on the memory of the 41st president. Important unity for the country. Jon Karl, thank you for your reporting. And our coverage of the celebration of George H.W. Bush continues tomorrow. The final service in Houston, that's at 11:00 A.M. Eastern tomorrow morning, right here.

This transcript has been automatically generated and may not be 100% accurate.