President George H.W. Bush on life and lasting friendships

On his 88th birthday, former President George H.W. Bush, is looking back on his life, relishing in the love of family and friends.

"I've been very blessed, when you look around, compared to ... others," the 41st President of the United States told ABC's "World News" anchor Diane Sawyer. "But you must feel responsibility to others. You must believe in serving others. I think that's a fundamental tenet of my life."

Bush's life story was the topic of a documentary titled "41," which premiered Thursday on HBO. The film is produced by Jerry Weintraub, who has been friends with Bush for decades.

"I don't know if it's been extraordinary for the president, but it's been extraordinary for me. He gave me a life and showed me things over the past 40-some years that never in a hundred million years would I have seen or been privileged to experience," Weintraub said sitting next to the former president at Bush's home in Kennebunkport, Maine.

"The biggest thing I learned from him was to respect other people. Not to be a braggart. Not to run around telling everybody how wonderful I am. That it'll all come to you if you work at it and work for it."

Watch Diane Sawyer's interview with President George H.W. Bush and Jerry Weintraub Friday on "World News with Diane Sawyer" at 6:30 pm E.T.

In the documentary, Bush remembers the first time he laid eyes on his future wife, Barbara, during a dance at the Greenwich Country Club.

"They called it a holiday dance at Christmas time and here she was in this red and green dress," Bush told Sawyer. "I said, 'Who is this good-looking girl, that beautiful girl over there?' 'That's Barbara Pierce from Rye, New York.' So then a guy named Wozencraft introduced us. And the rest is history."

While America's 41st president still follows politics and has endorsed Mitt Romney in this year's election, it does not consume him the way it once did.

"I keep up, in a way. But not — not in the detail I used to, not at all," Bush said.

Bush's son, Jeb, has said that the former president might have had trouble fitting in to today's Republican party. A claim Bush partially agrees with.

"I think that's true in some issues, in some — some contexts. But overall, I don't feel that way," he said. "I mean, it gets so locked in and so right. And it — it troubles me a little bit. But on the other hand, I don't worry about it a long time. I think — I think we'll be okay. ...I am an optimist about life, about the — everything that lies ahead."

What lies ahead for Bush is quality time spent with friends and family.

"I don't know what would happen — I don't know where — where I'd be in life if I wasn't blessed with a lot of kids and grandkids and family, including of course Barbara," Bush said. "Family means everything to me. And we're blessed a with lot of 'em. ...We take great pride in what they do and what their plans are for the future. And through — through their eyes, I think of life a lot."

The newest member of the family is Bush's great-granddaughter, Georgia Helena Walker Bush, who was born last summer.

"I have a little worry that I won't be around to see her grow much older. But it's not — it's not a fearsome thing," the former president said.

Bush says he is coming to terms with his own mortality and believes in an afterlife.

"I've wondered about [Heaven]. Who you see when you get there. Who do you look up? How do you find them? There's a lot of people there. Maybe you look around, find some didn't make it, too. So — I think — I don't know how that works. I don't think anybody knows," he said. "I don't fear it, though. When I was a little guy, I feared death. I'd be — I'd worry about it. I'd be scared. Not anymore."

Tess Scott and Margaret Aro contributed to this report.