"Their mom and dad were literally a quarter mile from the house to pick them up and go trick-or-treating," Nathan Bradley tells PEOPLE

Credit: courtesy Howard Family

When Georgia State Trooper Nathan Bradley rang the doorbell of the Howard family home in Newborn on Oct. 31, he had some heartbreaking news to deliver.

Donald and Crystal Howard, who had left to buy face paint and Halloween candy and were on their way home to take their four children trick-or-treating, had been killed in a car crash when their SUV skidded off the wet road and hit a tree.

But after being greeted by four smiling children ages 6 to 13 dressed as Freddy Krueger, Dracula, a wizard and a fire-fighting Ninja Turtle – who were excitedly awaiting their parents’ arrival – he had a swift change in plans.

“I thought, ‘Man, their Halloween is just going to be destroyed tonight,’ ” Bradley, 24, tells PEOPLE of the children – Justin, Amaya, Damien and Travion. ” ‘This is what they were looking forward to.’ Their mom and dad were literally a quarter mile from the house to pick them up and go trick-or-treating.”

Bradley stalled for the next hour as he and his colleagues searched the national databases for the closest relative. They were able to locate their paternal grandmother in Sarasota, Florida.

“She initially thought it was a Halloween prank,” Bradley says of his phone call to notify Stephanie Oliver, 55, of the news of her son and daughter-in-law’s deaths. “She was angry and yelled at me and I said, ‘Ma’am, this is not a joke,’ and I provided some personal information and said I was there with the children.”

Through tears, Oliver tells PEOPLE: “I was shocked. They were just two minutes away from home. I just freaked and half an hour later I was on the highway.”

With the permission of Oliver and the Department of Family and Child Services, Bradley decided not to tell the children of their parents’ deaths, but to wait for their grandmother to arrive the next morning to break the news to them in person.

In the meantime, Bradley would take custody of the kids for the night – and try to salvage their Halloween festivities.

When the kids told him that their parents should be home soon, Bradley replied: “Your grandma wants you to hang out with me until she gets here.”

He then asked: “Which one of you is hungry?” and told them to jump into his patrol car to go grab a bite to eat with him.

Bradley set off his flashing blue police lights to the delight of the children and made stops at all their favorite places: McDonald’s for Happy Meals and Burger King for Whoppers (with onions!).

The group then went to the Monroe State Patrol post and watched movies and ate candy until it was time for bed.

Bradley admits it was difficult to put on a brave face, knowing the children’s world was about to be turned upside down.

“It was dreadful,” he says. “I did some pretty remarkable acting. I have the worst fake smile in the world, but I wore it. It just tore me apart.”

During the time he spent with the kids, Bradley learned about their remarkable parents.

“They were responsible for homeschooling these kids and based on our conversations, they are all highly intelligent – they have really creative minds, the 13-year-old told me about some inventions he wanted to make to protect soldiers (his father Donald, 33, served in the Army for eight years, completing two tours in Afghanistan and Iraq. Crystal, 30, was a stay-at-home mom.)

“Those parents did a fantastic job, and it’s so sad that they can’t be here to continue that,” Bradley says. “Besides being intelligent, they were confident in everything they said and very well-mannered.”

When Oliver arrived at the patrol post at 6:30 a.m. the next morning, Bradley sat her down and answered all her questions about the fatal wreck.

“I explained that they exited the roadway – we’ve had a lot of rain recently and the shoulder became so saturated and soft – and they just weren’t able to get back onto the road before they struck a tree,” he says.

Oliver then went to wake the children up and they immediately ran into her arms.

“They hugged her and kissed her, and she’s crying because she knows the situation, but they thought she was crying tears of joy,” Bradley says.

As she loaded the kids into her truck, Oliver went over the Bradley and said, “I love you, I love you, I love you. Thank you for preserving their innocence,” Bradley shares.

“I know that meant a lot to her to be able to see her grandchildren one last time before their world changed,” he adds.

Oliver then sat the children down and told them of their parents’ death.

“They were okay, because they’re so little – the oldest one, he knows what’s going on – but the younger ones just cried and then they said, ‘Okay, grandma. We’re ready to go with you.’ ” she says.

The children will live with Oliver in Florida, where they will be placed into public schools.

“They’ve stayed with me before, they know what they’re going to and they’ll be with their cousins and will have family around,” she says.

The family received one final visit from Bradley before they left for Florida earlier this week. And when Justin opened the door, he walked straight into Bradley’s chest for a hug.

“He hugged me so tight I could feel it through my vest,” Bradley says. “I asked him how he was doing and he said it hadn’t really set in yet and he just kept asking why it was both of them. And I said, ‘That’s something we can’t answer buddy. Just stay strong and stay strong for your siblings.’ ”

Although they’re now separated by hundreds of miles, Bradley and the Howard family say they’ll stay in touch. There’s even plans for them to reunite at Bradley’s upcoming wedding in Georgia on Nov. 15.

“I’d love to have them there,” Bradley says. “It would be very important.”

Stephanie says there’s no way they’re missing it.

“We’re going to be the first ones there!” she says. “Because he is so wonderful, there’s no way in the world I wouldn’t be there for him. He took very good care of my grandchildren. I’m so proud of him.”

Bradley has also set up a GoFundMe account (which has already raised over $171,000) to help with the family’s funeral costs. Any additional funds will go into a trust for the kids’ education.

“It’s amazing how the country came together to support them,” Bradley says. “They’re no longer orphans. The country has taken them into their arms – they’re America’s children now when you think about it.”