AKCAKALE, Turkey — Some penniless parents who fled war-ravaged Syria are now so desperate to survive that they've changed their minds about ISIS — and are even happy that their kids have returned to fight for the militants.

While ISIS is all about creating an Islamic state, the group's appeal often can come down to a question of cash.

When Lufti first arrived in Turkey from Syria in late 2011, he thought his stay there would be short-lived. He was certain rebels would unseat Syria's president and he would be able to return home. But reality — and the struggle to support his wife and five kids — soon set in.

"No work, no school, no future ... They felt they were useless"

Two of his sons, Mustafa and Ahmad, quit school to find work. When it became clear the money he was earning from a workshop and from smuggling cigarettes was not enough, Mustafa decided to go back to Syria to fight.

"I didn't support his decision but I knew that we didn't have a lot of options," said Lufti, who spoke to NBC News on condition only his first name be published.

Mustafa first joined the Free Syrian Army — a rebel group fighting to unseat President Bashar Assad — in March 2014 aged just 18 but soon after switched to ISIS in hopes of better perks, Lufti said.

When 16-year-old Ahmad said he wanted to go to Syria too, Lufti hatched a plan to cut off his son's long hair in hopes it might keep him home out of embarrassment. But Ahmad was gone by the next morning: His mother had warned him about his father's plot.

Lufti said he understands what drove his children to join ISIS — and it wasn't the religious mores espoused by the Sunni militants.

"Both of them felt that they failed here in Antakya — no work, no school, no future," he said. "They felt they were useless."

Now, he said, they have friends and privileges they never could have imagined — along with their father's understanding.

"After all this time, I think that the boys took the right choice," Lufti said, with pride in his voice. "They get all the respect, the money, food, housing and the power… These are things that I couldn't offer them before in Syria or even in Turkey."

He added: "It's very painful when I think that my children are in a war zone and they could possibly die at any moment but I now understand their situation and I don't want them to come back."

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A United Nations report confirmed ISIS has used financial rewards to recruit children. While enlisting or conscripting children under the age of 15 is a war crime, ISIS has aggressively targeted them for recruitment or use in military operations. The militants also don't try to hide their young soldiers: They boast about ISIS "cubs," as they're called, in propaganda videos and photos.

An image taken from ISIS video purportedly shows Al Farouk training camp for "cubs" [children]. The camp is in Raqqa, Syria, according to Flashpoint Intelligence, a global security firm and NBC News consultant. ISIS video

Anwar, a 30-year-old Arabic teacher originally from Raqqa area of Syria, said he's seen several of his relatives join ISIS. He believes bad economic conditions and a lack of options are the main reasons driving the enlistment of youth.

"A lot of families send their children to ISIS as if they send them to school, especially if they're not working — at least the parents don't have to feed and clothe them," Anwar said from the Turkish border town of Akcakale. "These people need money and food and ISIS are now the only one who can offer that."

Experts, though, say the real picture is more complicated.

While money might play a role in the decision to join ISIS, it's certainly not the primary motivation — or why youth stay in the ranks, according to David Phillips, a former senior adviser to the State Department on Iraq.

"The problem revolves around self-worth," said Phillips, who is now director of the program on peace-building and human rights at Columbia University. "Radicalized youth join ISIS not because they're looking for a payout but because they're seeking meaning in their lives. They didn’t receive education or opportunity where they came from — they feel becoming a jihadi offers them an opportunity that didn’t exist back in the slums or villages from which they originate."

When Marwan told his parents he wanted to join ISIS, his mother Fatima tried convincing him not to go. She was scared for her son and at 16 thought he was too young to fight — but the teen's father, Shadi, did not stop him.

"I told him that if he wants to join them, I can't prevent him," Shadi, 49, told NBC News.

About three months after Marwan left their Syrian village near Tal Abyed for an ISIS training camp, he came home for a visit. Shadi said he noticed his son had "changed a lot": Marwan spoke passionately about his religious lessons, weapons training, Islam and infidels.

"I saw a man in front of me," Shadi said. "Not a spoiled child anymore who was running to the squares and parks to play football."

This photo obtained by NBC News shows three young ISIS volunteers near Raqqa, Syria. NBC News

Marwan brought more than religious fervor home, though — he also had around $250, sugar and rice.

"We were very happy because we needed both — the money and the food," his father said. After seeing Marwan safe and in good health, Fatima gave him her blessing to return to the camp.

On his last day home Marwan asked if he could bring his younger brother, Mahmoud, back to the ISIS training camp with him.

"We did not agree at first because Mahmoud was just 13 years old but when Marwan told us that their leaders told them that they would receive bonuses if they bring anyone from the family or the neighborhood with them to the camp we agreed and allowed Mahmoud to go," Shadi said. "Beside that, Mahmoud looked very happy to go with his brother."

When the boys came home for a visit more than two months later, Mahmoud told his parents he didn't want to ever go back to the ISIS camp — he wanted to stay with his sisters and mother.

"My wife and I talked with both kids and we told them that we don't want to put pressure on them," Shadi said. "If Mahmoud wanted to stay at home, we would support his decision but we also explained to them our living situation and that we need money."

Marwan insisted his brother had been happy at the camp and was afraid "he would face punishment if he returned without his brother," Shadi said, so both boys ended up going back to fight with ISIS in the countryside of Raqqa.

The rest of the family left their home in Syria for Turkey about four weeks ago when Kurdish forces seized the city of Tal Abyad. Since then, the only contact with the boys has been over the phone.

Marwan was shot in the leg about two weeks ago during a battle with Kurdish forces — and Shadi said he always fears the worst.

"I'm always afraid about them," he told NBC News from the Turkish town of Sanliurfa, about 16 miles from the Syrian border. "Every day when I wake up I am afraid that the phone rings and an ISIS fighter tells me that my son got killed."

Despite the risks at home, Shadi does not want to stay in Turkey.

"Life here is very expensive and we do not have the money," he explained. "We may go back to Syria … and live there in the land of the caliphate with our children."

Cassandra Vinograd reported from London.