Later this week, Carter's pastor reportedly said he was "up and walking" after his surgery

Close Friend Says Jimmy Carter 'Is Doing Fine' After Surgery — but Is Probably Missing His Sunday School Class

While Jimmy Carter remained hospitalized this week after surgery to treat bleeding on his brain from recent falls, the 95-year-old former president “is doing fine,” a longtime close friend tells PEOPLE.

“He is doing fine and is probably only uncomfortable with the idea that he had to cancel his Sunday school appearance,” says the friend.

Get push notifications with news, features and more.

President Carter has been a years-long fixture at Sunday services at his hometown church, Maranatha Baptist, in Plains, Georgia. Previous health issues, including a broken hip and surgery in May, have only temporarily stopped him from teaching on Sundays.

Later this week, Carter’s pastor at Maranatha also said he was “up and walking” after the surgery, according to USA Today. Rev. Tony Lowden said he visited Carter on Wednesday.

On Monday, The Carter Center, Carter’s humanitarian organization with wife Rosalynn, announced that he had been hospitalized in Atlanta in preparation for surgery Tuesday to “relieve pressure on his brain” following bleeding caused by a series of falls.

The next morning, the center said he was recovering after the procedure to treat a subdural hematoma and that there had been no complications. As NPR noted, the hours-long gap between him being hospitalized and the surgery suggests the bleeding, which was between his skull and his brain, was not imminently grave.

Typical treatment involves draining the blood through a hole in the skull, though doctors will actually take out a larger portion of the skull if the injury is more severe, according to NPR.

Image zoom Former President Jimmy Carter at Habitat for Humanity in October Habitat for Humanity International/

Image zoom From left: Former President Jimmy Carter and former First Lady Rosalynn Carter in 2018 John Amis/AP/Shutterstock

“President Carter will remain in the hospital as long as advisable for observation,” The Carter Center said Tuesday. “We do not anticipate any further statements until he is released from the hospital.”

“President and Mrs. Carter thank everyone for the many well-wishes they have received,” the center said.

Carter, who turned 95 last month, fell twice in October: once requiring stitches (and receiving a nasty black eye) and another time fracturing his pelvis in what his office said at the time was a “minor injury.” He also fell earlier this year, in May, and needed surgery to fix a broken hip.

He survived a bout with cancer in 2015, though he found then that he was “completely at ease” with dying, he has said.

R. Wayne Harpster, who has been friends with Carter since 1979, when Carter first came to fly-fish on Harpster’s property in Pennsylvania, told PEOPLE this week that “he’s a fighter and a loyal friend.”

“His faith has helped him a lot, his faith in God almighty, and another thing is his determination,” Harpster says. “He always has, since the first time I met him, he wanted to do the best and I think that kind of thing in a person — you will live longer and don’t give up.”

PEOPLE spoke with President Carter in October, a few days after he turned 95 and his first fall that month, which required stitches above his eye. Despite that, he and Mrs. Carter traveled to Nashville, Tennessee, for their annual volunteer project with Habitat for Humanity, building homes for those in need.