Nathan Barrett, the younger brother of Raptors star RJ, “fell ill and had been home for several weeks” before he died on Tuesday, according to Sportsnet’s Michael Grange.

RJ has been away from the team since Wednesday for “personal reasons.”

A cause of death for the 19-year-old, who had been studying to be a pilot, was not shared.

Like his older brother, Nathan played high school basketball at Montverde Academy in Florida as a 6-foot-1 guard.

Nathan was four years younger than RJ, who is 23.

“He’s growing up way too fast, every time I see him he’s getting taller, he’s like starting to wear my shoes now and stuff, so it’s crazy,” RJ told The Post’s Steve Serby in June of 2023. “He’s more a point guard, but he’s really aggressive.”

The family is headed up by former St. John’s basketball star and Canada Basketball GM Rowan Barrett and Kesha (Duhaney) Barrett, a Bronx native and track-and-field athlete at St. John’s.

“In my family we’re very competitive,” RJ told Slam in 2018. “Everyone is always trying to beat each other. Everyone is an athlete, so that’s where I get all my competitive drive.”

While RJ, now 23, went on to star at Duke before being selected with the No. 3 pick by the Knicks in the 2019 NBA Draft, Nathan opted for flight school.

According to a statement from the Barrett family, Nathan died Tuesday, surrounded by his family, church and friends.

“While our family is devastated by this great loss, we will continue to cherish the memories and time spent together,” the statement said.

“Nathan was a God-fearing young man of strong character. He was thoughtful, kind, loving, compassionate, creative, admirable and driven.

“Though his time with us was brief, he will live forever in our hearts.”