God honors faith even if it is misguided. If they act in faith, that is the most moral thing to do irrespective of the decision they may come to in this sad situation
Please, do give out this nonsense. Many people 'truly, sincerely' believe that they did 'nothing wrong', and God does not say "Well, no problem because they really thought it was ok."
Prov 21:2 "Every way of a man is right in his own eyes"