Alana McMullen underwent a nine-hour brain operation on March 14
Credit: Courtesy Alana and Ethan McMullen

Seventeen-year-old Alana McMullen suddenly started feeling ill after the holiday season. It would take several weeks before the Decatur, Mississippi, high schooler would find out that her mysterious symptoms, including vomiting and dizziness, were caused by something life-threatening.

“I would fall, and I didn’t even know what could’ve caused that or why it was happening. I had gone to the doctor three or four times during that time period, and they never figured out what was wrong with me,” Alana tells PEOPLE. “They did a bunch of tests that never were anything — they were inconclusive.”

In February, while on her way to play in a basketball game, Alana put her earbuds in and realized she couldn’t hear anything out of her left ear. After visiting an audiologist, then an ENT, Alana had an MRI performed that showed she had a two-inch tumor growing inside of her brain.

“I was shocked. I never thought it was that. I just thought that I lost hearing,” the high school junior recalls. “I was like, ‘Oh, I’ll get hearing aids.’ I never thought it was anything like this.”

Alana and Ethan McMullen dressed in their basketball uniforms
| Credit: Courtesy Alana and Ethan McMullen

For her older brother, Ethan McMullen, the diagnosis was devastating.

“I was crushed. My mom came and talked to me. I knew that if my mom came, it had to be bad,” Ethan, 19, says. “I was bawling my eyes out. When I saw her, she just had a smile on her face like nothing ever happened, so that just kind of inspired me to be strong through it all.”

Alana underwent a nine-hour surgery on March 14 at Le Bonheur Children’s Hospital in Memphis, Tennessee, which removed around 90 percent of the medulloblastomatumor. The operation left her with a 10-inch scar on the back of her head.

To show his support while his little sister faced her recovery, Ethan brought along a picture of her scar to his barber and had them recreate the same marks in his hair.

“I wanted her to see that she wasn’t going through it alone,” Ethan says. “That we had so many people backing her up, that it’s not just her.”

As Alana was recovering in the hospital, Ethan revealed his new hairdo by texting her a picture of her scar along with his cut.

“She thought it was really sweet,” he says. “And I mean, she was still on so much medication, still not feeling well, and she couldn’t really react too much, because she was really drowsy, but she thought it was really sweet.”

Though Ethan mentioned his idea for a haircut before she went into surgery, Alana says she was pleasantly surprised he actually followed through with it.

“I thought it was pretty cool. I didn’t know he was going to do it so soon. I thought he was going to wait a little while,” she says. ” I hadn’t even seen my scar until he sent me that picture. That was the first time I saw it!”

Alana posted a series of pictures to her Twitter account showing her scar and her brother’s matching haircut, and the post quickly went viral, racking up more than 104,000 favorites and more than 14,000 responses.

For many of those on Twitter, the loving gesture tugged at their heartstrings.

Alana is now keeping her positive attitude while preparing to start intravenous chemotherapy on April 10. Ethan—who is keeping his matching haircut maintained as his sister recovers—says if Alana loses her hair during treatment, he’ll be shaving all of his hair off as well.

“She’s inspired me so much. It’s crazy to have your little sister be one of the biggest inspirations in your life,” he says. “She’s just a super strong individual, who stays positive throughout everything, no matter how hard it’s been for her.”