John McCain's former cellmate in a Vietnamese POW camp says if anyone can beat a brain cancer diagnosis, it's McCain.

"I'm devastated. I'm devastated," said Col. John Fer, U.S. Air Force (Retired). "It's a very emotional time. A very emotional time."

Fer spent six years as a POW in Vietnam. For two of those years, McCain was his cellmate, along with about 50 other captured Americans.

As the son and grandson of Navy Admirals, Fer said the Vietnamese singled out the injured McCain for extra abuse. "He was really beat up. He was suffering a lot of broken bones."

Conditions were brutal. "Isolation, solitary confinement, torture abuse, coercion," said Fer.

But he said McCain never broke. And he doesn't think cancer will break him either.

"It will take a superhuman effort, if you want to put it like that, a McCain effort. A McCain effort."

Fer was a Air Force pilot, shot down while flying his electronic surveillance plane over an uncharted Vietnamese missile site.

He forged a bond with McCain and remembers the joy all the POWs felt when Vietnam released them. He has a picture of them lifting off and cheering. And another of his mother hugging him when he landed.

He hopes he'll get another chance to relive that joy with his hero. "I think of all the happy times we've had," he said about McCain. He's sent a get well soon message, but has not had a chance to talk to him.

Colonel Fer is deeply religious and goes to Mass every day. He said he's dedicated each Mass since he learned of McCain's diagnosis to his quick recovery.