Bergdahl is believed held somewhere in Pakistan, but the Taliban said they would free him in exchange for five of their most senior operatives at Guantanamo Bay, the American installation on the southeastern tip of Cuba that's housed suspected terrorists following the Sept. 11 attacks.
The militant group's exchange proposition came just days ahead of possible talks between a U.S. delegation and Taliban members.
Bergdahl's father, Bob Bergdahl, urged those gathered at Hailey's Hop Porter Park to remember everyone, regardless of nationality, who had suffered during the 12-year conflict in Afghanistan that began following the Sept. 11 attacks.
He described his son as "part of the peace process."
"I wish she was the only mother that was suffering in that way," Bob Bergdahl said of his wife. "Mothers all over the world are suffering because of this war, and I don't forget that for even one day."
He addressed his son's captors in Pashto, the Afghan language he's learned since Bowe Bergdahl went missing.
Bob Bergdahl, who has grown a beard and wore all black at Saturday's event, said that while he is physically in Idaho, he's living vicariously through his son, having set his cell phone to Afghan time, in a bid to share as much as he can his son's experience in exile.
Both mother and father talked of Bergdahl as an adventurer, a young man who once helped crew a sailboat through the Panama Canal, disembarked in San Francisco and then rode a bicycle south along the Pacific Ocean to meet family in Santa Barbara, Calif., 350 miles away.
He joined the military at 22 because "he honestly thought he could help the people of Afghanistan," Bob Bergdahl said.
On June 6, the family said it received its first letter from their son in his handwriting in four years, ferried through the International Committee of the Red Cross.