Southern California family raising awareness after losing child to rare brain cancer

Sebastian Daniel Guerra fought for months battling a rare brain tumor, but sadly passed away last week surrounded by his family. He was just 11-years-old.

“My beautiful son Sebastian was one of a kind. He loved life and had so many dreams,” said his mother Katie Mosier. “I am so proud of my brave boy for choosing to smile and make the best of every day even when the battle was very hard.”

The once energetic, dancing and vivacious boy was featured on KTLA after being diagnosed in January 2024 with Diffuse midline glioma (DMG) a fast-growing, aggressive pediatric brain cancer.

Unfortunately, due to the aggressive nature and position, the tumor was inoperable. Instead, Sebastian went through multiple radiation treatments and even clinical trials.

“He never complained. He just was like I can do this and he did it and it takes a lot of bravery,” Mosier said. “There are moments in this journey where it’s so hard because as a parent you have no control.”

Over the past year family, friends, and the community have stepped up to check off Sebation’s bucket list the best they could including a trip to Paris and a big 11th birthday celebration. Sadly it would be his last.

His family is now vowing to continue the fight to help to raise awareness in his honor.

“Sebastian loved his family and friends, but also every person he encountered. My boy deserved a fighting chance but unfortunately, pediatric cancer doesn’t get enough funding, especially for our brain tumor kids,” said Mosier. “Our family is devastated, Sebastian was the light of our family and no parent should have to watch their child die in their arms. We hope change comes for all children who face cancer.”

His family has donated Sebation’s tumors to hopefully provide more research to the foundation, https://giftfromachild.org/, to lead the fight for Sebastian and other children.

Sebastian will be celebrated in March. If you would like to help, you can donate to https://gofund.me/afecfb5f