As unfortunate and cruel as it will sound, the families pleas had little hope of doing much. This is the true nature of religion, cutting someone's head off and screaming about God while doing so. ISIS is too convinced they are doing what is right, and too firmly entrenched in the regions they now occupy taking advantage of a long term civil war in one nation and a weak government in another.
All that said we are here now due to decades of interceding in the region trying to convince a group of people to adopt western governmental and sociological ideologies that said people in the region have no aptitude for, and primarily because of this horrible religion they mostly follow.
Society will never advance all that far so long as we are held back by these relics of human design.