Transcript for George W. Bush to eulogize father
George W. Bush's family at the rotunda and want to go to Terry Moran. You covered president George W. Bush and that eulogy so difficult for him to deliver and something he's been preparing for his whole life as well. Reporter: He has. What a moment it's going to be, the 43rd president eulogizing the 41st, the son remembering his father, their unique relationship. There's no question that they were bonded together in history but they were very different politically really and when George W. Bush steps forward in the national cathedral it'll be hard not to remember that moment after 9/11 when he spoke to a shaken country, returned to the pew where his father, the president was, the proud dad there reaching across to grab his son's hand but for all their differences and all the talk of rivalry and competition, they shared a lot. They had that mischievous sense of humor, they had a unique way of mangling the English language, a deep pate terrorism and unbreakable bond of love. I'd like to shear a letter president George H.W. Bush wrote both his son, George, when he was running for president and Jeb for Florida governor, he wrote chart your own course. Not just on the issues been ow defining yourselves. No one will ever question your love of family, your devotion to your parents. And that, I think, defines the relationship that we'll hear about from George W. Bush today. This is a family that wears their emotions on their sleeves. I was struck by president George W. Bush's speech writer saying you have to strike passages about the elder president from George W. Bush's because he would break down whenever he talked about him. This will be a difficult eulogy to give. Reporter: He is like his dad and his brother, he wears his emotion on his sleeve and they were very, very close. As I say for all the talk of how different they were politically, they were very close and we will see that today, George. Okay, Terry Moran, thanks.
This transcript has been automatically generated and may not be 100% accurate.