George W. Bush, who followed his father to the White House after President Bill Clinton's 2 terms, sat in a front pew near the flag-draped casket and joined in as some 1,000 mourners sang "America the lovely".
The 42-year-old George P. Bush holds the office of Texas land commissioner.
In her caption, she mused that the 41st president's late wife, former first lady Barbara Bush, who died in April, was eagerly awaiting her husband's arrival in heaven.
"He was not considered a skilled speaker, but his deeds were quite eloquent and he demonstrated their eloquence by carving them into the hard granite of history", Baker said.
The legendary singing group shared their own fond memories of meeting Bush at the White House in the 1980s when he was the vice president -and how it sparked a decadeslong friendship.
There were emotional displays along the route in towns like Spring, Magnolia, Navasota and College Station. "But when the time came for prudence, he always maintained the greater courage of a peacemaker".
After the funeral, a hearse will carry the 41st president's casket from St. Martin's to a Union Pacific facility north of Houston near the worldwide airport named for him.
The Oak Ridge Boys recalled performing for him for decades - sometimes at the White House - and joked that Bush "fancied himself to be a good bass singer".
Following the funeral, the casket will be taken by train on a two and a half hour trip to allow people to pay their respects, as its destination will be the Bush presidential library located on the campus of Texas A&M University in College Station.
George P. Bush, son of former Florida Governor Jeb Bush and one of the former president's 17 grandchildren, remembered fly fishing and sharing ice cream with the man he called "Gampy".
The Grammy victor began honoring George H.W. Bush when she heard he passed away last Friday.
Former US President George H.W. Bush was laid to rest at his presidential library in College Station, Texas, on Thursday, following funeral services at his longtime church in Houston.
McCain walked to the casket with tears in her eyes.
Wednesday night, more than 11,000 people paid their respects as Bush lay in repose at the church all night.
President Donald Trump and his wife Melania were joined by the Obamas and Clintons on the front pew.
Former President George W. Bush and Laura Bush hold their hands over their hearts as they wait for the casket of former President George H.W. Bush on December 6, 2018 in College Station, Texas.
The cathedral service was a tribute to the patriarch of one of the nation's most powerful political families - they occupied the White House for a dozen years - and to a faded political era that prized military service and public responsibility.
On Thursday, Baker pointed to Bush's eagerness to forge compromise and peace rather than rattle sabers. Apart from courteous nods and some handshakes, there was little interaction between Trump and the others. He took comfort in knowing "Dad is hugging Robin and holding Mom's hand again".