It’s “a bittersweet thing” for a Tennessee man, who will be receiving a kidney from his son, who died Sunday from injuries suffered in a car crash earlier this month.

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Luther Davis of Maynardsville has had dialysis treatment for the past five-and-a-half years, the Knoxville News Sentinel reported. His son, Nathan, had been trying to lose weight in order to meet the criteria for donating a kidney for his father.

Nathan Davis’ mother, Julia Davis, knew her son had signed up to be an organ donor in case of his death. She did not know that her son was hoping to help his father out as a living donor.

"Nathan was trying to get himself in a condition health-wise, weight-wise, so that he could be able to donate as a living donor," Julia Davis told the News Sentinel. Nathan Davis had only told his sister of his plans, Julia Davis said, because he "wouldn't want to raise hopes and not be able to follow through."

Those plans appeared to be shattered when Nathan Davis was involved in a car crash Jan. 8, the newspaper reported. The 23-year-old, who was a passenger in the car, suffered a severe head injury and died early Sunday.

However, a representative from Tennessee Donor Services visited Luther Davis and asked if he would want to receive a kidney from his son, the News Sentinel reported, bringing tears to the older man's eyes.

"It’s the most paradoxical thing I can imagine, to be so utterly devastated in one part of your heart and so overjoyed in another part of your heart at the same time," Julia Davis told the newspaper. "I can’t describe it, but it was like a trickle of electricity that went through me when he told me that. And it made me cry."

"It's a bittersweet thing," Luther Davis told the News Sentinel. "I'm glad to have the kidney, but I would have loved to have had it any other way."