ATLANTA (AP) — Jimmy Carter's grandson says the 91-year-old former president is doing well while undergoing cancer treatment and showing no sign of slowing down, despite his pledge to do just that.

"There has been no evidence of that at all," former Georgia state Sen. Jason Carter said Wednesday at an Atlanta Press Club meeting, prompting laughter in the audience. "Absolutely none."

When the elder Carter announced in August that cancer had spread to his brain, he pledged to step back from work at the human rights organization he founded after leaving the White House. The Carter Center's full-time staff would carry on, aided by his grandson as incoming chairman on the organization's board.

Jason Carter took on the job last month — but he says his grandfather is maintaining his busy schedule, not pulling back.

Jason Carter said the former president "feels good physically," and has received good medical reports from his doctors. Jimmy Carter and former first lady Rosalynn Carter "are in a remarkable place spiritually and emotionally," he said.

"Their peace with where they are in their lives and where they've been in this world has really allowed them to take in this outpouring of support that has just been incredible," he said. "It takes an incredible human being to have a diagnosis like this be almost a happy time for them."

Jason Carter, who ran unsuccessfully for Georgia governor in 2014, said the human rights organization headquartered in Atlanta is financially prepared to continue monitoring elections and fighting disease around the world whenever his grandparents decide to step back.

"It is their living legacy," he said. "It has been their home and their headquarters for all the issues they cared about most: peace, justice, human rights, mental health, alleviation of suffering across the world and especially among the world's poorest people."

Jimmy Carter's spokeswoman released a statement in November, reporting that Carter was responding well to treatment and no evidence of new tumors had turned up. Carter received a radiation treatment in August aimed at four small tumors on his brain and regular doses of Keytruda, a newly approved drug to help his immune system seek out any cancer cells appearing elsewhere in his body.

Doctors also removed melanoma from his liver.