"In lieu of flowers or gifts," the couple requests that those willing to give "please send donations to Dell Children's Medical Center in River's name"

Granger Smith is grieving the loss of his youngest child.

The country singer shared the “unthinkable” news on Twitter and Instagram Thursday that his and wife Amber’s 3-year-old son River Kelly died “following a tragic accident” where “despite doctor’s best efforts, he was unable to be revived.”

Get push notifications with news, features and more.

“Amber and I made the decision to say our last goodbyes and donate his organs so that other children will be given a second chance at life,” Smith wrote, sharing along with a smiley photo of himself and River.

“Our family is devastated and heartbroken, but we take solace in knowing he is with his Heavenly Father,” added Smith, who is also father to son Lincoln Monarch, 5, and daughter London, 7.

Image zoom Courtesy Smith Family

“Riv was special,” he continued. “Everyone that met him knew that immediately. The joy he brought to our lives cannot be expressed and his light will be forever in our hearts.”

“If there are words to say more, I cannot find them in this moment,” Granger concluded. “Love the ones close to you. There has never been a more difficult moment for us than this.”

Alongside a selfie with her son, Amber shared the same heartbreaking caption, beginning it with, “Nothing can prepare a mother to deliver this kind of news.”

“In lieu of flowers or gifts,” the couple requests that those willing to give “please send donations to Dell Children’s Medical Center in River’s name. The doctors, nurses and staff have been incredible.”