SAN FRANCISCO (CBS SF) — A man who donated his deceased son’s organs years ago is getting paid back in kind from the mother of the transplant recipient who benefited from the organ donation.

A grieving Bill Millard and his wife made the decision to donate their 20-year-old son Kalem’s organs after he was killed in a 2005 ATV accident.

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Millard’s son’s donated pancreas saved the life of Janice McKinnon’s son Jake. Now, McKinnon’s organ donation will save the life of Millard.

Millard has kidney failure from years of diabetes and has been on dialysis for three and a half years.

On Friday, Millard and McKinnon, will undergo surgery at California Pacific Medical Center in San Francisco to remove one of McKinnon’s kidneys and transplant it to Millard.

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“It’s hard for me to wrap my head around it, because 10 years ago we donated my son’s organs and that is actually saving my life now,” said Millard.

It almost didn’t happen.  Most donor families stay anonymous.   But the two families met and became good friends and each year light a Christmas tree to remember Kalem.  It was at last year’s ceremony that McKinnon announced her gift.

“I think this is an extraordinary way to give back a gift that you have received,” said CPMC transplant surgeon Dr. Janet Bellingham. “But I’ve never heard of this before…I’ve never heard of this before.”

The fact that Janice would be a match to the man who saved her son has both families thinking this was meant to be.  And it’s why she doesn’t fear the operation.

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“We are where we’re at for whatever reason-and it’s gonna be fine,” said McKinnon. “’Cause it’s unbelievable that we’re even here, I think.  Yeah.”