"My dear mother had to give him CPR until the paramedics came," Jeremy Carter's brother writes of his death
Credit: Ben James

Jimmy Carter‘s grandson Jeremy died suddenly on Sunday, after suffering a heart attack in front of his mother, who performed CPR and tried desperately to save him, according to an emotional blog post by his brother Josh.

Josh also writes that Jeremy underwent “a whole battery of tests just a couple months ago.”

“He couldn’t eat well and his legs ached. He had nearly every doctor at Emory look at him. They ended up prescribing him Vitamin A and Vitamin D. After all that. He got the full work over and really just needed vitamins. If a 28 year old heart is going to go out, shouldn’t they have found that? Maybe, but they didn’t,” Josh sys.

Jeremy was the middle child of Jeff and Annette Carter, according to USA Today. Jeff, 63, is the third of Jimmy and Rosalynn Carter‘s four children. Jeremy and Josh’s cousin Jason Carter is a former state senator who ran for Georgia governor in 2014.

Former president Carter, 91, announced his grandson’s death while teaching a Sunday school class at Maranatha Baptist Church in Plains, Georgia.

Jimmy, who announced he was cancer-free during another Sunday school class earlier this month, told the church that his grandson wasn’t feeling well when he went to take a nap at his family’s Peachtree City, Georgia, home on Saturday. His mother, Annette, went to check on him and discovered that his heart had stopped. He was taken to a hospital, where he died early Sunday.

“Jeremy was in Trauma 1 in the ER,” Josh writes. “He was not responsive. His temperature was low. His organs were not working. He was bleeding. He was yellow. I find out later that he had a heart attack at home while alone in the kitchen with our mom, my dear mother had to give him CPR until the paramedics came, and they took him to the ER.”

Jeremy’s cause of death is still unknown and the case is currently under investigation, Fayette County Coroner C.J. Mowell Jr. told The Associated Press on Monday. The state medical examiner’s office is assisting.

Opening up to his Sunday school class just hours after Jeremy’s death, Jimmy described his grandson as “a very special child” and “a wonderful young man whom we loved very much,” NBC News reports.

The former president urged the congregation to “be filled with a sense of joy and thanksgiving,” despite his family tragedy, The Atlanta Journal-Constitution reports.

“I should be joyful and thankful to God for giving me both life and freedom,” he added.

Reporting by ELISSA ROSEN