The story seems to have originated from an interview with the Director of a Christian Missionary organisation on US ABC Television.
// An ISIS fighter from northern Syria, veiled as a refugee, arrived at a Jordanian camp with the intention of killing Christian workers, but he abandoned his plans after hearing the Gospel and "witnessing the love of Christians."
"He first saw how Islam brainwashed him about Christianity, and how that contrasted with the reality of what he saw in the Christians," the ministry director that could not be named said. "And we're talking about an area of Jordan that has three Salafist [a strict, fundamentalist branch of Sunni Islam] mosques. They raise up people to go and fight."
The militant convert was so excited about his new found faith that the director had to "calm him down" to dispel threats he began receiving from other jihadists who wanted to kill him after his conversion. //
It could have happened like that, but it sounds like a wonderful fund raising story designed to get Americans to donate $$$.