By Chloe Melas

CNN

(CNN) -- Randy Travis credits his recovery from a life-threatening stroke to "amazing grace."

The country music star was hospitalized in 2013 for viral cardiomyopathy, a disorder in which a virus attacks the muscles of the heart, causing it to beat more slowly. That led to congestive heart failure, which caused a stroke that Travis unable to walk or speak.

But nearly four years later, the six-time Grammy Award winner, is defying the odds.

Travis told CNN during a phone interview on Saturday that with intensive physical therapy, he's doing "good."

The singer's wife, Mary Travis joined him on the phone and compared her husband's recuperation to "giant baby steps."

"It's little things that mean so much when you're recovering from a stroke," Mary said, while speaking to CNN from BeautyKind Unites: A Concert for Causes. "We never know when the end point is but we're happy with every little change, every little sound, every little word, every new task."

A major milestone came recently when the couple was driving through Tennessee.

"We were coming out of Memphis and overhead was a sign, 'Nashville' and he was over in the passenger seat and went, 'woo hoo' and he pointed up and he said, 'Nashville.'" she recalled. "I just sat over there in the driver's seat and cried because I knew then that he read that sign, and he recognized the word, and then he said it, that's a huge thing. Huge for us."

Randy, who was inducted into Country Music Hall of Fame in October, brought the audience to tears when he sang "Amazing Grace."

Mary said the song is his anthem.

"Going through this ordeal with his health, stroke and flatlining and making it back, when there was every opportunity in the world for God to take him home ... we've truly lived the life of amazing grace," she said.

When CNN asked Randy if he hoped to record music again, he said enthusiastically, "yeah, yeah, yeah!"

Music has been instrumental throughout Randy's recovery, according to his wife, but only recently could he listen to his own songs.

"Music is his soul," Mary said. "It was really hard for him soon after the stroke to listen to his music. I remembered when I first put his music on, he cried and I thought, ok, we're not ready for that."

But now, she added, he'll listen to his hits, "Diggin' Up Bones," "He Walked On Water," along with gospel music.

As for worrying about setbacks with his recovery, Mary said the idea of another stroke "doesn't enter our minds."

"We are onward and upward."