Jackson James Rice, an 18-year-old who was set to become the first Caucasian to represent Tonga in the Olympics, died over the weekend in a tragic diving accident mere weeks before the Summer Games.

Rice, who was born in the U.S., died at Faleloa on the island of Ha’apai in Tonga. Though born in the U.S., Rice grew up in Ha’apai, where his parents run a tourist lodge.

“I was blessed with the most amazing brother in the whole world, and it pains me to say that he’s passed away,” Rice’s sister, Lily, wrote on Facebook. “He was an amazing kitefoiler, and he would have made it to the Olympics and come out with a big shiny medal. He made so many amazing friends all over the world.”

Authorities believe Rice died as the result of a shallow water blackout while free diving from a boat.

Rice had planned to compete as a kitefoiler in the upcoming Olympics. In kitefoiling, a relatively new Olympic sport, a rider uses a foil board with wings attached to the bottom. These wings allow the rider to “fly” at high speeds above the water.