Dillon Hill, 19, decided to leave college to complete a bucket list with his best friend, Chris Betancourt, 20, after Betancourt learned his cancer had spread. (mybestfriendslist.com/Youtube)

When 20-year-old Chris Betancourt received a devastating cancer diagnosis, he cried for a week. But then, with the help of his best friend, he embarked on the to-do list of a lifetime.

Betancourt and Dillon Hill, 19, have been friends since the fourth grade, when they met in elementary school in Carmichael, Calif. The two immediately bonded over video games. So when Betancourt was diagnosed with Stage 4 chronic myeloid leukemia in May 2009, Hill visited him every day, and played video games to lift his spirits.

Chronic leukemias are very difficult to cure but generally progress slowly and can be treated. After chemotherapy treatment and a hospital stay in 2009, Betancourt recovered and remained virtually cancer-free throughout most of his teenage years. Inspired by their time playing video games in the hospital, the friends started Gamers Gift, a nonprofit that brings virtual-reality equipment to assisted living facilities and hospitals to help residents and patients escape their current realities.

Then in September of this year, Betancourt got the news that his cancer had returned, and this time it was resistant to medication. Doctors told Betancourt that he only has one or two years to live, unless he finds a bone marrow donor match.

[A depressed fan tweeted at Dan Harmon. His response brought many to tears.]

Betancourt was devastated, but not defeated.

“After how long I’ve dealt with cancer, it’s definitely a little bit hard to be blindly optimistic,” he said. “But  if you’re constantly worried about it, you’re going to get in a bad place. I’m trying to maintain a level of hopefulness.”

Hill has found a way to help Betancourt stay hopeful. A few days after the diagnosis, Hill told Betancourt to come up with a bucket list for the two to accomplish together. They opened up the list to the Internet, accepting suggestions from people who have lost their own loved ones. In November, Hill announced in a Facebook post that he was dropping out of college at the University of California, Davis, to help his best friend live life to the fullest, in what may be his final years. The pair got to work.

Dillon Hill dropped out of college to help his friend, Chris Betancourt, who is dying from cancer, complete items on his bucket list. The two delivered food to the homeless on Nov. 23, (mybestfriendslist.com/YouTube)

Items on Betancourt’s bucket list include “Lift weights with The Rock,” “Have a pillow fight with complete strangers,” and “Be in a video game.”

“There are some things I’m looking forward to and not looking forward to, like skydiving,” Betancourt says. “I don’t like heights, but I feel like that’s just one of those things you have to do.”

Betancourt and Hill are documenting their bucket list journey in videos posted online. The friends say neither of them expected their story to garner so much attention.

“When we were filming the first video, I told Chris, we need to explain this effectively, people have to know who you are, because I thought 10,000 people would see it,” says Hill.

Two weeks later, the video has more than 200,000 views.

[She gets a bouquet of birthday flowers every year from her dad, who died four years ago]

The two friends are raising funds online to help with travel costs as they try to complete the 79 items on the bucket list. On their fundraising page, Hill notes that he is also working to help fund Betancourt’s experiences, however, “it’s just not enough.” The pair continue to update the list as more adventure awaits.

While Betancourt and Hill are preparing for the worst, they’re also hoping for the best. The two are also using their Internet presence to locate a bone marrow donor.

Betancourt’s chances of finding a match for a bone-marrow transplant are low. There is a relatively small pool of potential matches from people of Puerto Rican descent and his progress is further hindered by the island’s slow recovery from Hurricane Maria.

Betancourt is enrolled in every bone marrow registry. “We can hopefully use this story as an outlet to spread awareness for bone marrow transplants,” Betancourt says. “If it can’t save me, at least it can save some someone else.”

Hill says Betancourt is an inspiration and credits his dark sense of humor that allows him to turn tragedy into laughter.

“He’s had every reason to give up, yet here we are,” Hill says. “This is about documenting Chris’s life, but it’s also about celebrating. It’s about remembering this might be our last day and trying to spread that idea to people to try and make them happier and open their eyes up to how awesome life is and how fragile it is.”

Elyse Samuels contributed to this report.