Twelve-year-old Kaden Koebcke was diagnosed with a kidney disease at two years old and has been on dialysis ever since. The boy from Georgia got his first kidney transplant from his dad at five years old, but his disease reoccurred just five days after the surgery.

Kaden has tried several different treatments for his focal segmental glomerulosclerosis (FSGS) throughout his life. The most recent one, chemo dialysis, was not working. "That's when we thought, 'We need to find a donor quickly,'" Kaden's mom, Cami Koebcke, told CBS News. The boy didn't just need a donation -- he specifically needed a living donor, willing to give up one of their kidneys.

The Koebckes had exhausted their donor options, the mom said. No one in their family was compatible with Kaden. Finally, Kaden received great news from his doctor -- they found a match. Little did the family know, the donor was someone they already knew.

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"[At first], we didn't know who the donor was due to HIPPA laws," Koebcke said. "We thought, 'Well, we don't know who it is, but we hope we find out. We hope they come forward.'"

About a month after Kaden's doctor told them they found a match, the donor revealed himself. "We're friends with the donor," Koebcke said. "He's Kaden's teacher."

Koebcke said Kaden received his kidney from William Wilkinson, who has been the boy's technology teacher for several years. "His family came over to our house and we were talking and he said, 'Do you guys want to find out who the donor is?' And we said, 'Yes, we want to thank him and hug him,'" Koebcke said. "And Mr. Wilkinson said, 'Well, it's me.'"

"He was shocked. He just couldn't believe it. I mean, he was just like, 'Wow,' almost speechless," Koebcke said of Kaden's reaction to his teacher's big reveal.

The Wilkinsons and Koebckes are family friends, and their sons are in the same grade at Grace Christian Academy, where Wilkinson also teaches.

Koebcke knew the teacher started the process of finding out if he was a donor candidate months ago, but she assumed he wasn't a match when she didn't get an update. Wilkinson broke the news to the family in May and the teacher and boy had their surgeries on Tuesday.

"Both surgeries went great," the mom told CBS News one day after the procedures. "Actually, I just talked to [Wilkinson's] wife and he's just taking his first walk around today."

Kaden's surgery also went well. The family was nervous that, like in the past, this procedure wouldn't work, but "his lab numbers are now heading in the right direction, he's alert and feels good, and is in good spirits," his mom said. "So we are definitely heading in the right direction." She said there is no cure for FSGS, but she hopes this transplant means no more dialysis for Kaden.

Kaden and Will are both doing well!! Kaden had a great night. He feels pretty good. Thanks to your prayers and our... Posted by Kaden's Kidney Search on Wednesday, August 15, 2018

Kaden is entering the sixth grade, but won't be able to return to school for about two months. Wilkinson should be back to work in three to six weeks, Koebcke said. Kaden is in the ICU and cannot have visitors, but his mom said he's already Skyped with his teacher-turned-donor.

"You can't thank a person enough. There's just no words. He's given Kaden the biggest gift you can possible give somebody," Koebcke said. "He's his hero, there's nothing short of that. He such a nice, kind and generous man, and we are just so so thrilled he was willing to do this."