Former president Jimmy Carter's 28-year-old grandson died Saturday, according to a report.

Carter, 91, announced the sad news during his weekly Sunday school lesson in his hometown of Plains, the Atlanta Journal-Constitution reports. The former president was 25 minutes late for his lesson, reportedly the only time he's ever showed up late. The younger Carter laid down to take a nap on Saturday at which time his heart stopped beating, the former president said before starting his lesson. CNN reports that Jeremy's family began giving him CPR and rushed him to a nearby hospital.

He died early Sunday, with a cause of death yet to be determined, the AJC reports. Outpourings of support are coming in from across the country, with noted civil rights activist Rev. Jesse Jackson sending out the following tweet Sunday afternoon:

Two weeks ago, Carter was able to announce to his class that the cancer in his brain was gone.

Carter was diagnosed with cancer in August after having surgery to remove a lesion on his liver. After having the surgery, Carter announced that the cancer had spread to other parts of his body. Doctors had found melanoma lesions on his brain.

He announced that he would significantly cut back on his schedule while undergoing treatment for his diagnosis.