Herzl Shaul, whose son’s remains have been held by Hamas since the 2104 Gaza war, was buried after dying of cancer.

Herzl Shaul died Friday at the age of 54, less than a year after being diagnosed with intestinal cancer. He was buried Sunday in northern Israel.

Even during his illness, he worked tirelessly for the repatriation of his son Oron Shaul’s body, as well as that of Hadar Goldin, who also was taken by Hamas during Operation Protective Edge. Both soldiers were later declared dead by the Israeli government in consultation with religious and medical authorities.

“Herzl Shaul was a brave man and until his last days he fought to return his son’s remains for a Jewish burial. At the same time, over the past year, he was compelled to fight the cancer with which he had been stricken. I saw him several times and on each occasion, from meeting to meeting, he appeared more gaunt, and heroically met the double tragedy that befell him and his family,” Israeli Prime Minister Benjamin Netanyahu said in a statement following Herzl Shaul’s death.

“The State of Israel will continue to do all it can to fulfill the obligation upon it to bring Oron to rest alongside his father, Herzl,” Israeli President Reuven Rivlin said.

Hours before his death, Shaul asked his son Aviram Shaul to promise that he would not rest until his brother was returned to Israel, Israel Hayom reported.

“I very much wanted and prayed to [be able] to see Oron brought back, but I didn’t have any more strength. They exhausted me and broke me. I’m asking you to promise me that you won’t break and you’ll bring Oron back to your mother,” Shaul told his son.

Herzl Oron is survived by his wife and two sons.

Also Friday, Aryeh Bar-Natan, whose only child, Haim Bar-Natan, was killed in the first Lebanon War nearly 25 years ago, committed suicide on his son’s grave in the Mount Herzl cemetery in Jerusalem.

Bar-Natan also was suffering from cancer and visited the grave daily, saying it helped him feel better, according to reports.