Former president Jimmy Carter, 99, turned to his son several weeks ago as he watched President Joe Biden, 81, announce that he was passing the torch to a younger generation and said softly, “That’s sad.”

Carter and Biden are friends and share much in common as members of the elite group elected to the White House. Biden is the oldest to ever serve and Carter has outlived all others. Neither went to Harvard or Yale. Biden is the son of a used-car salesman and Carter’s father ran a peanut farm. Now, both will be one-term presidents.

Carter has been in hospice for 18 months, and his health slipped further after his wife, Rosalynn, died in November, two members of his family said. But recently, as the former president’s 100th birthday approaches on Oct. 1, he is talking more, asking about the fast-changing 2024 presidential campaign and delighting in the momentum behind Vice President Kamala Harris, the new Democratic nominee. He is even eating mini cupcakes — red velvet and caramel are his favorites.

James Earl “Chip” Carter III said in an interview with The Washington Post that his father spent days watching all of the speeches from the Democratic National Convention last month that he recorded for him. “He thought Michelle Obama was the best, and he thought Kamala was great, too,” he said.

For Carter’s birthday next month, a concert in Atlanta, a 100-mile bike ride near his hometown of Plains, Ga., and other events are planned. But when Chip Carter told his father that many people believe he is trying to stay alive to reach his birthday, “He said he didn’t care about that. It’s just a birthday. He said he cared about voting for Kamala Harris.”

Carter’s state of Georgia is critical to the November election. Biden beat Donald Trump in 2020 by less than 1 percent of the vote in the state, and Carter’s family said he can’t wait to cast his mail-in ballot for Harris.

“He does not believe Donald Trump should be president again,” Chip Carter said.

“I’ll never lie to you,” Carter famously promised in his 1976 campaign that followed Richard M. Nixon’s lies about his involvement in the Watergate scandal. Carter has said one of the many things that upsets him about Trump is that he does not tell the truth. Fact-checkers at numerous media outlets have documented Trump’s many falsehoods, including the lie that Biden stole the election from him in 2020.

Trump has long derided Jimmy Carter as the worst president in history, and more recently has said he thinks Biden may be worse. After losing his reelection bid to Ronald Reagan in 1980, Carter began a post-presidency of humanitarian work. He won the Nobel Peace Prize in 2002 for his efforts to promote democracy, human rights and better health worldwide.

Though his vital signs are good and he is eating well, Carter remains very weak and some days are better than others, his family said. He needs a wheelchair to get around.

“After my grandmother passed, he had a pretty long low period when he wasn’t really engaging much at all,” said Jason Carter, his eldest grandchild. “But now he’s talking about politics again.”

On Aug. 18, Rosalynn’s birthday, the former president was brought to her grave at the edge of a pond in front of their home.

“He was looking at her tombstone and I started talking, and he told me to be quiet,” Chip Carter said. For about 20 minutes, his father sat in silence looking at where his wife of 77 years was buried last year. “No doubt he was praying, but he could have been just having a conversation with Mom,” Chip Carter said.

The next day, the Democratic convention started and Carter began tuning in to the presidential race. He had been shielded from TV news, especially reports about the Israel-Gaza war, for fear it would upset him.

Carter had brokered the 1978 Camp David Accords, a historic peace agreement between Israel and Egypt. Earlier this summer, Chip Carter said his father was worried about how Israeli Prime Minister Benjamin Netanyahu was handling the war and told him, “I hope Joe [Biden] doesn’t let Netanyahu bring him down,” noting that he believes Netanyahu supports Trump.

So until recently, Carter’s TV often had been turned to baseball games and the wholesome 1950s sitcom “Leave It to Beaver.”

Then Chip started playing the Democratic National Convention campaign speeches. “It took most of the day to watch the convention session from the night before with some breaks,” he said. His father was captivated, commenting on the speeches and saying how well Hillary and Bill Clinton, Obama and others did. “He is big time interested in this campaign,” his son said.

Jason Carter said Harris’s vice-presidential pick, Minnesota Gov. Tim Walz, “has some Jimmy Carter vibes.” Walz is the first person on a Democratic ticket who did not attend law school since Carter. Carter graduated from the U.S. Naval Academy. Walz earned a graduate degree in education at the University of Minnesota.

Carter, who has a long record of promoting women and African Americans, wants to live to see Harris elected. During his 1977-1981 administration, Carter appointed the first Black woman ever to serve in the Cabinet, Patricia Roberts Harris, who served as secretary of housing and urban development.

Carter enjoys hearing updates about the family farm, where 1,400 acres of longleaf pines were recently planted. He smiles when he hears about Habitat for Humanity. Jimmy and Rosalynn Carter for years led home-building efforts with the group, and to mark his birthday, country music stars Garth Brooks and Trisha Yearwood, friends of the Carters, will lead a project to build 30 homes in St. Paul, Minn.

His family and the Carter Center in Atlanta have scheduled several events to honor the landmark birthday, including a Sept. 17 concert of pop, rock, country, jazz, hip-hop and classical music by Chuck Leavell, D-Nice, Drive-By Truckers, Maren Morris, Carlene Carter, the B-52’s and other artists. It will also feature former Atlanta Braves star Dale Murphy, rapper Killer Mike and actors Sean Penn and Renée Zellweger.

Carter still has very difficult days, and no one is sure how long he will live and what keeps him going.

“I really don’t know what to make of it,” Jason Carter said. “I really think at this point he has given up his thought of being in control. I think he is waiting for God’s plan to run its course.”