"I believe in miracles, and when it happens you have to pinch yourself," Holly Hoyle O'Brien tells PEOPLE
Credit: Michelle Bruzzese

For weeks early this year, nurse’s aide Matt Nelms had been bugging his bosses at Doctors Hospital of Sarasota to hire a former coworker of his, Meagan Hughes.

He succeeded and Hughes was hired in February. But Nelms then implored his supervisors to make sure Hughes, also a nurse’s aide, worked the same daytime shift and on the same floor as he did.

That dogged determination led to the most improbable of reunions.

Hughes, 44, would soon discover that another nurse’s aide working the same shift on the same floor – and with whom she had become good friends – was her long-lost half sister, 46-year-old Holly Hoyle O’Brien. The pair had been separated and orphaned over 40 years ago in their native South Korea.

“I believe in miracles,” O’Brien, who started working at the hospital just two months before Hughes, tells PEOPLE, “and when it happens, you have to pinch yourself and ask, ‘Is this really happening?’ ”

In 1971, when O’Brien was 2 and Hughes an infant. Hughes’s mother – and stepmother to O’Brien – took Hughes away one night, a memory she vividly recalls. O’Brien’s alcoholic father died three years later after being hit by a train, and she ended up in an orphanage.

Hughes, meanwhile, somehow ended up in the same orphanage as her half-sister; she tells PEOPLE she has no recollection of her mother or her time in Korea.

Both were later adopted by American families, with O’Brien growing up in Alexandria, Virginia, and Hughes in New York, California and Florida.

Hughes gives Nelms all the credit for the sisters’ reunion.

“If I didn’t get my foot in the door,” says Hughes, “the three of us would be living our normal lives.”

Nelms had hounded the managers on his floor “once a week” to hire Hughes, even sticking a reminder Post-it note on nurse manager Julie Bennett’s computer.

“Finally they got tired of me saying, ‘Will you talk to Meagan,’ and they got her in here for an interview and they liked her instantly,” Nelms, 36, says.

Bennett interviewed both O’Brien and Hughes for their positions and played a part in their hiring and assigning them to the same shifts. Yet she won’t take any credit. “That part,” she says, “is just fate.”

O’Brien first learned of her new co-worker from a patient. “The patient said, ‘Hey, there’s a girl named Meagan, she’s from Korea, maybe you need to talk to her and get to know her,’ and I said, ‘Okay, I’ll give it a shot.’ I think I came by and said, ‘Hi, I’m Holly.’ ”

Bennett witnessed the pair instantly hit it off, bonding with their similarly warm personalities and passion for helping patients.

“At their core, they are just wonderful ladies,” says Bennett. “I am just so happy for them. It’s amazing. I still can’t believe it.”

Before learning they were sisters, Hughes and O’Brien became close friends. Outside of work, they would meet for lunches at P.F. Chang’s and visit each other’s homes some 25 minutes apart. They discovered they were each from South Korea, were in orphanages and had been adopted by American families.

It was almost five months after meeting that Hughes and O’Brien discovered they had the same Korean last name, Shin, prompting them to take a DNA test. On August 17, they received the results.

O’Brien first found out the results via email from the testing company. “I printed out the paper and I was completely stunned, I said, ‘This can’t be, ” says O’Brien.

She immediately texted Hughes the amazing news. “I was working that day and when I got the text, I was working with a patient and I had to keep my composure,” recalls Hughes. “I was shocked.”

While Hughes has no memory of her time in Korea, O’Brien says she “knew I had a sister somewhere out there. I had that intuition.”

Says Hughes as she starts to cry, with O’Brien quickly embracing her: “I told Holly from the bottom of my heart, ‘Thank you so much for not giving up. ”

Both sisters are equally appreciative of Nelms for not giving up and call him their “spirit brother.”

“For all the dominoes to fall like this is just crazy,” says Nelms.

For more on Meagan Hughes and Holly Hoyle O’Brien’s incredible story, pick up this week s issue of PEOPLE, on newsstands Friday.