'A typical Aussie kid' who a Sydney family wants home

According to a relative, Mohammed Noor Masri didn't show much interest in religion growing up.

"We're not a very religious family, to be honest," the stepbrother of the Sydney tradesman said from the front porch of his Roselands home.

"How and when and why he ended up over there is beyond my understanding."

"Over there" is northern Syria, where Masri is being detained after he and other followers of Islamic State surrendered to Kurdish forces in Baghouz a month ago.

His much older sibling, who declined to be named, said Masri had been a "typical Aussie kid" throughout his youth who "never did anything to anyone".

"It's really sad," the man who claims to be his stepbrother said, adding he wasn't even aware the 26-year-old had journeyed overseas.

Australian born Mohammed Noor Masri from Roselands in Sydney is in Kurdish custody in Northern Syria. Credit: Kate Geraghty

He said the last time he had seen Masri was about seven years ago. Back then, he had never openly expressed any desire to travel to the Middle East and was busy working as a fridge and airconditioning electrician.

Masri told the Herald that he travelled to Syria in January 2015 and joined what he now accepts is  an "evil" terrorist organisation as a misguided devotee of Islam. He said he never engaged in fighting, instead putting his trade skills to use in a hospital.

His stepbrother, who describes his younger sibling as a "reasonable" and "honest kid", said it was not like Masri to join such a brutal organisation.

Masri has since married an Australian woman and has fathered three children, with a fourth child on the way - a fact his Sydney relative said he'd only heard a few weeks before.

The stepbrother wants to see Masri return to Australia safely, along with his new family.

"At the end of the day, I want him home."