Looks like if they suffer from cognitive dissonance because, else, they would have to regocnize that their choices led to their daughter’s death.
As Carl Sagan wrote in The Demon-haunted World:
One of the saddest lessons of history is this: If we’ve been bamboozled long enough, we tend to reject any evidence of the bamboozle. We’re no longer interested in finding out the truth. The bamboozle has captured us. It’s simply too painful to acknowledge, even to ourselves, that we’ve been taken. Once you give a charlatan power over you, you almost never get it back.