CLAYTON COUNTY, Ga. -- As police continue to search for the driver involved in a deadly Labor Day hit-and-run, the victim's family is trying to learn how to live life without him.

Demosthenes Kostapapas, Jr. was hit and killed by a car in Clayton County on Monday, Sept. 4. Family told 11Alive's Joe Henke the 31-year-old new father was on his way back home to Reddick, Florida, after spending the weekend in Atlanta to attend Dragon Con.

According to police, the Florida resident was driving his Interstate-approved scooter south on I-75 Monday when he was hit from behind by the driver of a gray Honda Civic, throwing him from the vehicle. Authorities say the driver of the Honda kept going and exited Tara Boulevard.

When responders got to the scene, they found the 31-year-old lying in the roadway. They took him to the hospital, but Kostapapas later died from his injuries. His death was just one in a string of deadly accidents involving motorcyclists over the Labor Day holiday weekend.

Kostapapas' mother, Michelle Richter wonders if her son would still be alive if the driver had only stopped to help. "Had that person done the right thing, you know, my son may have survived," she said. "I don't know."

Richter said she found out about the accident through police, who broke the news to her Monday morning. She said the phone call is "every mother's worst nightmare."

"I just kind of fell to pieces at that moment," Richter said.

Richter said Kostapapas was an Army National Guard with a six-month-old child, still learning how to be a father. Now, she's coming to Georgia to collect her son's things, with his death still weighing heavy on her.

"(I'm) trying to accept that fact that he is gone," she said. "Everything you think about is all the would-of, should-of. I wish I would have done this. I wish I could have done that."

Investigators are now hoping a clue from the scene will help them track down the driver, now wanted for vehicular homicide. A piece of the car's body was recovered, helping authorities narrow down the model to a 2011 4-door Honda Civic. Anyone who may have information or witnessed the crash is asked to contact Clayton County Police or Crime Stoppers at 404-577-8477.

Meanwhile, Kostapapas' family is now turning to the task of arranging his burial, though they're asking for help to do so. According to the family's Gofundme page, the 31-year-old did not have insurance because he thought he was covered by the VA. That wasn't the case, though. They're now trying to raise funds to cover the cost of a casket, plot and services by the funeral parlor.

"He always tried to make the best of a situation," said Kostapapas' sister Michelle, who drove from North Carolina to meet him for the convention. She was the last one to see him alive. Michelle said they're now trying to make the best of this heartbreaking situation by remembering his spirit.

"He was always trying to crack a joke," she said. "In light of that, we have been trying to keep his spirit alive."