Robert Irwin is one proud little brother.

While speaking exclusively to PEOPLE at the Disney 2026 Upfront event on Tuesday, May 12, the conservationist, 22, was full of praise for his big sister Bindi Irwin as he touched on her ongoing journey with endometriosis and how open she has been about her experience.

“Bindi’s journey with endometriosis has been amazing because it’s hard to battle through that. And it’s easy to just let it be a silent kind of battle,” Robert tells PEOPLE of Bindi, 27. “But she’s decided to actually amplify that, to spread her story, to share that with people, to help other people. That’s a brave thing. That’s a challenging thing.”

“And endometriosis is a very hard thing to go through that so many people sort of suffer in silence or suffer undiagnosed,” he continues. “And I really just try and follow her lead. She’s amazing. Anything that I can do to amplify this message of women’s health that she spearheads so well, I mean, sign me up. I’m there.”

“So I’m a very proud younger brother,” the Dancing with the Stars winner adds. “She is amazing in everything she does, and I’m just here to back her 100%.”

Bindi was diagnosed with endometriosis in 2022, shortly after welcoming her 5-year-old daughter, Grace, whom she shares with husband Chandler Powell. She shared her diagnosis publicly in 2023.

According to the Mayo Clinic, endometriosis is an “often-painful condition in which tissue that is similar to the inner lining of the uterus grows outside the uterus.”

Robert’s kind words for his sister come after he and their mom, Terri Irwin, shared an update on how Bindi is doing as they explained her absence from the third Steve Irwin Gala, an annual event hosted by Terri, Robert and Bindi to fund and continue the conservation work their late husband and father Steve Irwin was so passionate about.

“Bindi is doing so much better now … Things like a lot of travel are a bit challenging for her at the moment and so she’ll be here next year to celebrate this wonderful night,” Terri, 61, told E! News at the gala in Las Vegas earlier this month.

“This year she’s just staying a little close to home. So, ironically, it’s less taxing for her to be home feeding crocodiles,” she added, referencing the family’s Australia Zoo in Queensland.

Back in March, Bindi revealed that she had had 50 lesions, caused by endometriosis, “cut out of my body” over the last three years as she shared a series of photos of herself in the hospital.

“I’ve felt indescribable, inescapable pain,,” she captioned a March 30 Instagram post. “Trying to keep my invisible illness to myself after being told by doctors it was just ‘part of being a woman.’ I spent 10 years being undiagnosed. As a teenager and young woman, I felt weak and deeply insecure. I was trapped in my own body.”

“March is endometriosis awareness month. As this month comes to a close, I urge everyone to remember this invisible disease each and every day,” she continued, “To lend support, compassion and grace towards the millions who suffer. It’s up to all of us to raise awareness, not just for endometriosis but for women’s health as a whole. No one deserves to suffer in silence.”