Cagney Wenk, of Boulder, was diagnosed with an inoperable, stage 4 glioblastoma last month, just three weeks before his fiancee Jessica Li was due to deliver their baby boy.
"Just the emotions of having a baby in general is enough for one couple to handle," Wenk's sister, Marissa told InsideEdition.com.
Doctors moved quickly on his treatment, including three brain surgeries, but when Li went into labor, the community rallied around the family to make sure Wenk would be able to witness his son entering the world.
"It was a possibility [he wouldn't be there]," Marissa said.
At the time, Wenk was still in the ICU following a surgery, but with the help of nurses who volunteered to watch him and wheel his bed and medical equipment to Li's bedside, he was able to be present in the room as Li gave birth.
Wenk was wrapped in bandages in his hospital bed on the opposite side of the room until moments after Li delivered her baby. Nurses wheeled their two beds next to each other, and Wenk could be seen in his son's birth story sobbing, as he held Levon in his own arms, and reached out to his fiancee.
"We have all the love in the world around us right now," Wenk said, according to the birth video.
"She's a rockstar," Marissa said about her future sister-in-law. "I wouldn't say she was nervous, that's just not how she is. She was just really excited to meet the baby."
Marissa told InsideEdition.com Wenk still has about 4 weeks of radiation and chemothrapy left in his treatment plan.