Melissa Bowman(NASHVILLE, Tenn.) — A 4-year-old cancer patient who lost his hearing during treatment is “overjoyed” to receive his first pair of hearing aids, and you can watch his reaction in a new video.

“As soon as they put [the hearing aids] in and turned them on, he was like a whole new child,” his mother, Melissa Bowman, told ABC News’ Good Morning America.

The video captured the moment that Xander Bowman, who has stage 4 neuroblastoma, was able to hear after losing his ability because of an “intense” chemotherapy drug called Cisplatin. This side effect is common in children like Xander with high-risk neuroblastoma, according to the National Center for Biotechnology Information.

After his “superhero ears” were turned on, Xander grinned at the camera and danced around the doctor’s office at the Vanderbilt Bill Wilkerson Center in his hometown of Nashville, Tennessee.

“Before he got them, he was constantly asking me to repeat myself. He would get very frustrated that he couldn’t hear what I was saying,” Bowman said.

She worried if Xander would like his hearing aids because he’s “sensitive” about his ears. But after seeing his giddy and giggly reaction, she knew that his “whole new set of ears” made him happy. And they still do.

“I was overjoyed. It made me feel so good that he felt that good,” Bowman said.

Even Xander’s doctors have been touched by the sweet moment caught on camera by Bowman’s boyfriend, Alex Pennebaker, and posted on the Sarah Cannon Cancer Network’s Facebook page.

“Even after doing this for 20 years, it brought tears to my eyes … just to see his reaction was really amazing. I don’t know how else to describe it,” Dr. Jennifer Domm said.

Domm works as a pediatric hematologist and oncologist at the TriStar Centennial Women and Children’s Hospital in Nashville. She called Xander “remarkable” and said that even though his kind of cancer is “very very difficult” to treat, Xander brings joy to her and the other members of the medical staff.

“You would never honestly even know that he’s sick, which is part of the amazing thing about Xander,” Domm said.

But for Xander and his loved ones, things haven’t always been this happy.

The last nine months have brought bout after bout of bad news for the family. He was first diagnosed with cancer at age 3 in January after experiencing “severe” back pain.

Xander started chemotherapy immediately to battle the cancer that had already spread throughout his body. He has a large tumor growing out of his upper back bone as well bone marrow disease and bone lesions in his legs, his pelvis, his spine and his skull.

His diagnosis requires long stints of intense treatment, which has been “difficult” for Xander, his mother and his 3-year-old-sister Olivia, who often has to be left with relatives during hospital stays.

And so far, treatment has not worked.

“I didn’t think it would ever happen to us,” Bowman said.

Bowman opened up to GMA and shared that in addition to the shock of her son’s sudden diagnosis, she has struggled with anxiety and panic attacks.

“There would be mornings where I would wake up, and the first thing I thought about was losing my son. I couldn’t live like that anymore, so I got help,” Bowman said.

She also told GMA that she now seeks counseling and takes medication, which has helped alleviate her fears and depression. She said that she’s doing “a lot better now.”

“I try not to look at the future. I try to just focus on the day that we’re in and enjoy everything we do together and enjoy his smile,” Bowman said.

Like Bowman, Domm said she remains “cautiously optimistic” for the future, and she expressed some confidence in new treatments for Xander.

“I’m always hopeful, and I think we’ve identified some potential new options,” Domm said.

She offered advice to parents who hear stories like this and fear their children might suddenly develop cancer, and she cited Bowman’s actions as a prime example of what to do.

“If a parent thinks that something is not right, just keep asking for answers,” Domm said.

Bowman offered her own advice to parents and families currently facing similar situations with sick or suffering loved ones.

“Just know that it gets better. That it gets easier,” Bowman.

As for Xander at the moment, Bowman said he’s having a blast and acting like any other 4-year-old. He and his family are on a trip to Disney World for Xander’s Make-A-Wish.

“He’s got so much personality. He just remains happy through all of this. He draws people to him … he’s a good little boy,” Bowman said.

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