Stop pretending to a humanity your people lack. I already experienced how you deal with things like this. "Honor your father and mother" extends to abusive parents, as I'm sure you know. You never define 'mother or father' but the obligations could fill a Manhattan phone book with two-point font, every one of them insulated against change of any kind by saying they are done with Daas Torah. Like I said, you treat people willing to trust you in bad faith. Every yeshiva student I've talked to goes immediately into 'how to answer the heretic' mode. So let them hash it out with the Cossacks once more, because that will at least remove the notion that lying makes them safe from their twisted minds.