Mark Russell, a father still grappling with the loss of his son to a fatal fentanyl overdose, is pushing for the punishment of the person responsible.>> Download the KOCO 5 App"Graham was extremely bright, intelligent, handsome," Russell said. His son was a junior at the University of Oklahoma at the time of his death. "I'm still in shock today, and it's been four and a half years," Russell said. For four-and-a-half years, Russell has been fighting for justice while the person who gave Graham the fatal dose of fentanyl moved through the court system. "I encourage parents and guardians who have lost kids to this horrible, horrible drug, don't take no for an answer," Russell said. However, the plea deal, which will drop the murder charge, does not bring closure for Russell. "The case is finished, but it's not finished. We also looked at it as an opportunity to help other families with some of the components of the plea deal," he said. Russell is now pleading with other families to pay attention to their children. "One, know who your kids are hanging out with, know who their friends are. Don't ever think it can't happen to your kid," Russell said. Get the latest news stories of interest by clicking here.Despite his struggle, Russell said he remains hopeful about the justice system. "I'll eventually learn to forgive her, and oddly enough, I've been including her in my prayers lately. That's really hard," he said. As the sentencing of the person responsible for Graham's death approaches, the Russell family said they hope that it will close a chapter that has felt never-ending.In an effort to combat the ongoing opioid crisis, several Narcan and fentanyl testing strip vending machines have been installed across the state. Top Headlines TIMELINE: Oklahoma could see severe storms with hail, tornado risk late Monday 2 bodies recovered in rural Texas County, OSBI says 4 arrested for first-degree murder in connection to 2 women missing from Oklahoma Panhandle How to reduce your carbon footprint FBI opens criminal investigation into Baltimore bridge collapse, AP source says