An Arizona couple whose 15-year-old son died after being accidentally shot at a sleepover is opening up about their loss to educate other parents about the dangers of unsecured firearms. 

Bruce and Claire Petillo had their lives change forever on September 5, 2021, when their youngest child, Christian, was shot in the chest while spending the night at a friend's house. 

The teen was rushed in an ambulance to a nearby trauma center, where he underwent surgery for the gunshot wound, but he didn't survive. 

'Even to this day, 18 months later, and it still feels like a nightmare,' Bruce, 52, told Today of his son's tragic death. 'It still doesn't seem real. I'm still waiting for him to come walking in the door.'

The parents, who also have a 26-year-old daughter and 24-year-old son, shared how Christian was the baby of the family and always doted on. 

Claire described him as being a 'very infectious kid' who 'loved his friends,' as well as a talented athlete who mastered everything from baseball to skateboarding. 

Christian was in the eighth grade at the start of the COVID-19 pandemic, and they recalled how the school shutdowns made the transition from middle school to high school difficult for him. 

Claire said he 'dealt with bullies and bullying,' which is partially why they let him sleep over his friend's house that night despite their initial hesitation. 

The teen had previously shown an interest in going shooting, according to the Arizona Mirror, and his parents had agreed to take him to a range and teach him gun safety after he turned 16.  

Hours before his death, he had been shooting Airsoft guns — replica firearms that fire plastic BBs — with his friends and had asked to spend the night at one of their houses. 

The Petillos don't keep guns inside their home, and it didn't occur to them at the time to ask if the other teen's parents had weapons of their own. 

Christian's friend allegedly brought out one of his family's unsecured firearms and passed it around to the small group of boys in his bedroom during the sleepover. 

Authorities are still investigating what happened that evening, but at some point, the gun went off, and Christian was accidentally shot in the chest near his collarbone. 

Bruce and Claire said they were home watching a movie when they received a call from an unknown blocked number around 9:30 p.m. that they let go to voicemail.

A few minutes later, their daughter called and told them that Christian had been shot and they needed to call the sheriff. 

The parents rushed to the hospital where their son was taken and were told his prognosis 'didn't look good.' 

Bruce said he prayed in the chapel while Christian was in surgery and 'begged God not to take him' before they were told their son didn't make it. 

Guns are the leading cause of death among American children under the age of 19, according to a paper published in the New England Journal of Medicine last year. 

For decades, vehicle crashes were the leading cause of death among the age group, but that changed in 2020. More than 4,300 children aged 1 to 19 years old died of a gun injury during the pandemic's first year — a nearly 30 percent jump from 2019. 

Following Christian's death, Bruce and Claire are focusing on raising awareness for the prevalence of unsecured firearms and advocating for common-sense gun laws. 

The gun safety advocacy group Everytown reported there were at least 2,070 unintentional shootings by children resulting in 765 deaths and 1,366 nonfatal gun injuries between 2015 and 2020. 

An estimated 4.6 million children live in a home with loaded and unlocked firearms, according to the results of a 2021 national firearms survey. 

Bruce and Claire shared that they never imagined something like this could happen to their family, and they are now urging other parents to ask about unsecured weapons before letting their children go over someone else's house.    

'Parents need to be able to have that conversation with another family,' Bruce told Today. 'Say: "I'm just wondering, do you own guns? And if you do, are they properly secured?" 

'It does a couple of things: One, it creates an open dialogue. It also makes everybody aware, and helps enhance accountability and responsibility for those firearms.'

The father said parents who receive a 'negative response' to their questioning should 'take it as a sign' that this is not a place they want their child to be. 

'I think that the vast majority of gun owners are responsible,' he noted, 'and the ones who own these guns and are responsible are going to say: "Absolutely, we have it secured."'

Claire added that parents should also tell their children that they will pick them up 'no questions asked' if they ever find themselves somewhere with a gun. 

The Petillos, who are promoting gun safety through their website NoDoOvers.org, are also working with legislators on the state and national levels to pass gun laws.

They have teamed up with Kristen and Michael Song, whose teenage son Ethan also died after being shot with an unsecured gun, to pass Ethan's Law, which would make proper firearm storage a federal requirement. 

Ethan's Law passed with bipartisan support in Connecticut in 2019.

The couple is advocating for a similar law, named Christian's Law after their late son, in their home state with the help of Democratic Arizona State House Reps. Jennifer Longdon and Jennifer Pawlik. 

'Christian’s Law is not taking away a thing,' Claire told the Arizona Mirror. 'It’s not taking away anyone’s Second Amendment right. You are welcome to own guns. But please be responsible and lock them up.' 

The law would require gun owners to either keep their firearms locked in a storage container or use a safety device that would make the weapons inoperable without a combination or key. 

'Safely storing firearms can reduce gun injuries and deaths, and is supported by researchers, healthcare professionals, and gun owners alike,' according to John Hopkins Bloomberg School of Public Health. 

However, Arizona House Rep. Kevin Payne, who is the chairman of the Military Affairs and Public Safety Committee, told 12News KPNX on Monday he will not give the bill a hearing.

'If someone needs to get to their weapon in an emergency, they don't need to be undoing locks,' he said.

Bruce told the news station that Payne's comments won't stop them.

'We're not going away,' he said.