(INSIDE EDITION) -- A Florida teen with terminal cancer will get his wish to marry his high school sweetheart this weekend.

Dustin Snyder, 19, and Sierra Siverio, 21, have been dating since Siverio's senior year of high school. The pair had previously known each other in the sixth grade, but they lost touch when Snyder moved to another school.

That was until 2015, when Siverio walked into a Steak and Shake where Snyder worked to fill out a job application. She immediately recognized him.

“He was just standing there,” Siverio told InsideEdition.com. “I got the job. Dustin and I were both in relationships but eventually, we got together.”

In May 2016, the pair moved in together at Snyder’s mom’s house. But, a short time after the move, Snyder began feeling ill.

“We thought he pulled something playing baseball or football,” Siverio said. “He was complaining of chest pains in the middle of the night and he woke us up saying he wanted to go the hospital. That’s when they said they found a mass in his left lung.”

On Snyder’s 18th birthday, June 28, 2016, he was diagnosed with synovia sarcoma, a rare cancer. He underwent chemotherapy and doctors removed the affected lung. The cancer was gone for two months after treatment before it returned and began spreading.

A month ago, Snyder was rushed to the hospital when he started experiencing abdominal pain. His cancer has returned and he has several tumors in his stomach and around his pelvis. Doctors said there isn’t anything they can do.

He has been hospice care since.

“The doctor said it could be days, weeks, possibly even a month,” Siverio said. “Monday we were talking and we brought up marriage. He told me he knew he wanted to get married and I was the love of his life. And we were like okay ‘let’s make it official.’”

The couple plans to get married this Sunday at The Big Red Barn Venue in Oak Hill, Florida.

After Snyder’s sister started a GoFundMe, hundreds of people have donated toward the couple's special day. The page has received more than $23,000 as of Saturday.

A wedding dress, tuxedo, photographer and their venue have been donated to Snyder and Siverio.

“It’s mind-blowing how many people have donated. We’re grateful,” Siverio said.

The couple will put a chair to the side during the ceremony because Snyder can’t stand for extended periods of time.

“I love him so much,” Siverio said. “It was one of the things I was hoping for us in the long run before this happened. We are not thinking about an ending date for him. We are just enjoying the time we have together.”