A grandfather from Arizona is fighting to make every moment count after receiving the devastating news that his aggressive cancer has returned.

His daughter Kamryn Quackenbush (@kmquack) posted a heartbreaking clip on TikTok of her father, William, bonding with her newborn baby.

At 28 weeks pregnant, Kamryn was shocked when she learned of her father’s diagnosis during a family visit home for Christmas.

“My parents sat down my sister, myself and my boyfriend when we came home for Christmas and let us know that my dad’s routine PET scan showed his cancer has come back and spread to his lungs,” the 28-year-old told Newsweek. “It truly felt like our whole family’s worst nightmare was happening.”

As a soon-to-be mom, Kamryn couldn’t cope with the reality that her dad may have limited time.

“All I could think about was that the best dad in the world wasn’t going to get the time he deserves being the best grandpa,” she said.

Determined to defy the prognosis, Kamryn’s dad threw himself into every possible treatment avenue—conventional and holistic.

The day after the family received the news, William started a therapeutic low-carb diet that eliminates dairy, grains, sugar and processed foods. His regimen also included daily infrared saunas, meditation and a rigorous supplement routine.

Simultaneously, William pursued second opinions from top cancer institutions, including Mayo Clinic and MD Anderson. Ultimately, he transferred his care to MD Anderson and began immunotherapy.

As Kamryn prepared to welcome her baby, her parents decided to live with them for two months.

“[It was] such a huge help, but beyond that, [there were] invaluable moments between my dad and my daughter,” Kamryn said.

Every morning, William would wake up in the early hours so his daughter could sleep in.

“He just wanted to spend time with his family and especially his granddaughter; there’s nowhere he wanted to be but here,” Kamryn said. “It was simultaneously the sweetest time of my life watching it and the hardest knowing that it won’t always be able to be this way.”

The heartbreaking clip has been met with love from other TikTok users. Hundreds of comments, prayers and messages of support have poured in.

“May he get as much time as humanly possible with all of you,” one user wrote.

“Praying alongside you for that miracle,” added another.

“I feel so grateful and humbled that so many strangers are taking time out of their day to send my dad well wishes, prayers, offer kind words, encouragement and support,” Kamryn said.

But, despite William’s efforts, follow-up scans have concluded that immunotherapy and holistic treatments were not working.

William’s cancer had spread to the lining of his lungs—a more-serious progression. Without hesitation, her parents relocated to Houston to be near MD Anderson for a new, aggressive treatment plan: four rounds of dual chemotherapy and immunotherapy.

Kamryn said that the side effects are brutal, and her dad has lost all his hair, and developed mouth sores, rashes and neuropathy.

Above all, pride in her father radiates through every word. “My dad is one of the best people I know,” Kamryn said. “He is patient, empathetic, humble, and so much more. He has maintained all of who he is while being faced with unfortunate circumstances, and I am so proud every day to call him my dad and my daughter’s pop pop.”