Single dad adopts 13-year-old who was abandoned 2 years earlier at hospital

"From day one, he's always called me 'dad.'"

A 13-year-old boy who was abandoned by his parents has found a forever home.

On Nov. 12, Tony Mutabazi was adopted by his foster dad, Peter Mutabazi in Charlotte, North Carolina. Tony had been in the foster care system since the age of 2, and at the age of 4, Tony was adopted by a couple in Oklahoma. No details are known about his birth parents.

"He's the nicest, smartest kid I've ever had," Mutabazi told "Good Morning America." "From day one, he's always called me 'dad.' He truly meant it and he looks up to me. He's proud to show me at school and say, 'Hey, he's my dad.' That's something that I love about him."

When he was 11, Tony's adopted parents left him at a hospital and never returned, according to Mutabazi and foster care worker Jessica Ward.

"He asked if his parents were coming to get him and they said no," Mutabazi said. "[We have] no idea why."

On Jan. 16, 2018, Muatbazi received a call from Ward asking if he could take Tony for the weekend.

Mutabazi, who's been a foster parent for three years, said he was originally supposed to have Tony stay at his home for the two days. But then he learned Tony's story.

"By that time, I was crying. I thought, 'Who would do that?'" Mutabazi said. "Once I knew the parents' rights were signed off and he had nowhere to go, I [knew] I had to take him."

Tony and Mutabazi have been together ever since.

Mutabazi, who grew up in Uganda, said he ran away from his abusive home at the age of 10 and found a parent figure who guided him through school.

"They became my sponsor, my family. I grew up the poor of the poorest people on the planet," Mutabazi said. "I grew up where no one told me to dream, that there was no future for me."

Mutabazi eventually moved to the United States and became a citizen. He works with the nonprofit organization World Vision United States, which helps kids living in vulnerable areas. Mutabazi has also fostered 12 children.

After meeting Tony, Mutabazi decided to legally become his father.

"I had the room, the resources, so I had no reason to let him go," Mutabazi said. "For what someone did for me I wanted to do something for someone else."

Tony's adoption was made official in a Charlotte courthouse. The moment was captured by photographer Cole Trotter among Mutabazi's family and friends. Mutabazi recently shared the story on how he adopted Tony with Love What Matters.

Ward, who works with Angels Foster Family Network in Edmond, Oklahoma, said she helped facilitate Tony's adoption, which was eventually finalized when Mutabazi and Tony moved from Oklahoma to North Carolina.

"[Tony] had some issues that he was dealing with from foster care and trauma when he was abandoned, so Peter know once he took him in, that was it," Ward told "GMA." "Peter's [Mutabazi] story all around is beautiful and amazing. Because of the age Peter was when all of the things happened in his world, I feel like that's been such a connection for him and Tony."

Mutabazi said he and Tony enjoy watching movies, playing board games, reading books and bicycling together.

He and Tony are looking forward to welcoming a new foster child, who will join their home in the near future.