Sabri knew his mother would never let him enter the bloody chaos of Syria, so he invented a wedding to go to instead.

A 19-year-old from Vilvoorde, Belgium, he traveled first to Turkey in August 2013, then crossed the border with Syria to join his newfound “brothers”; he never elaborated on the group’s allegiance. By the time his mother, Saliha Ben Ali, discovered his room empty the morning of his departure, he was already on his way to joining the ranks of some 6,500 Europeans designated as foreign fighters in Syria. She subsequently found a wrinkled gray djellaba — the traditional robe he said he would wear at the wedding — hidden under his bed.

Sabri — who took the nom de guerre Abu Turab, one of the Prophet Muhammad’s companions — later told his mother that he had found his mission “taking care of the sick and children orphaned” by the civil war. Ben Ali, while acknowledging her son’s radicalization, hoped he wasn’t fighting for a group responsible for brutalizing swaths of the country.

His disappearance would lead his mother to her own mission: helping spearhead a national campaign aimed at deterring young men from violent ideologies — a journey that would see her feature in a French anti-radicalization video to be aired nationwide and sign what was called a mothers’ charter at a meeting in Vienna.

But before turning to the plight of others, her energies were devoted to saving her son. A long, painful conversation on Facebook between mother and son ensued over the course of six weeks, in which they exchanged more than 2,000 messages and she begged him to come home, often three times a day. “It was my way of getting through the day,” she said. “So I could continue to talk to him.” In October he asked for money. His parents’ refusal was the last message in the chain. Two months later, her husband received a phone call from an unknown acquaintance of their son in Syria: He had died as “a martyr,” the man said.

It took just 20 seconds to learn about his death, but understanding more about why he went to Syria would take a lifetime, she told Al Jazeera.

“My life project today is to try to understand why our children are obliged to go and die to feel useful,” she said. “That’s my life question.”

“I couldn’t accept the way he died. That was too unjust for me,” she said.