Last October, Kai Johns, an Army veteran and engineer for Sprint, was told by doctors that both of his kidneys had failed and he needed an immediate transplant. After seeing a post on Facebook, an old friend of his from the Army, Robert Harmon, offered to help, reports Fox 5 DC.

Robert Harmon sits in Medstar Georgetown University Hospital before the surgery.

"It was a Facebook post. It said, a kidney for Kai," Harmon told Fox 5 DC. "I Facebook messaged [his wife], and ask her, what could I do to start getting tested."

Johns and Harmon have known each other for 22 years. The two served in the Army as paratroopers at Fort Bragg, North Carolina, but had not seen each other in over 15 years.

Kai Johns awaits the kidney transplant surgery from Robert Harmon that will save his life.

"We were paratroopers in the Army together and that brotherhood runs deep," Harmon said. Harmon, 42, is a telecommunication operations chief at the 3rd Infantry Division Sustainment Brigade at Fort Stewart, Georgia.

Kai Johns hugs his wife before surgery at Medstar Georgetown University Hospital.

Johns was diagnosed with polycystic kidney disease, which affects around 600,000 people in the United States alone. After getting tested at the MedStar Georgetown Transplant Institute in Washington, DC, he learned that he would get the kidney he needed. And on April 27, Harmon donated a kidney to Johns. The three-hour surgery was performed by Dr. Jennifer Verbesey at Medstar Georgetown University Hospital.

Surgery for the kidney transplant is underway.

"For someone to step up and just save your life — you can’t come up with a word for it," Johns told Fox 5 DC.

To cover the costs of the procedure, the family has been holding several fundraisers and started a website for donations. Currently they have raised $30,870 of their $75,000 goal. To help the Johns’ family, click here.