It is irrelevavt that is a fictional scenario. The scenario with Jews was not.
The situation differs form that of the Nazis and the Jews.
With the Nazis looking for Jews, they were not requiring a sin to save a Jewish person. They just asked a householder if there were Jews there, or something along those lines. In fact, they probably didn’t even usually ask; they probably just barged on in to look for themselves, because of course, they wouldn’t *believe *a negative answer. Notice that our police officers do not ring people’s doorbells and ask if they have evidence of a crime in their house–they just get a search warrant and look for themselves.
If the Nazis were to ask the question, a mental reservation could be used: There are no Jews here [in the foyer]. I saw the Rosen family on the other side of town [last month], I was seeing some friends (if asked why one was out at night), because the Nazis were asking a question, ***not *
requiring one to sin as the OP proposed.
You wouldn’t be able to tell a lie to save a mans life. That is a problem. You have placed a law above Loire and charity.
Now that the difference between the situation with the Nazis and the fictional scenario is clear, let’s look at the fictional scenario.
One could trick the would-be murderer by telling a truth that he would not believe.
One could commit a sin.
Committing a sin is not only not acceptable for a Catholic, it would be completely ironic, because it is an offense against God Who allowed His Son to be killed that we might live. God gave up the life of His Son for us, but we will not give up the life of our child for Him?
You say that by refusing to commit a sin, the parent would be placing “a law” above love and charity. But we are talking about God’s Law, not a civil law, and God’s Laws are based on love. Our first love must be for Him, because every human person we have on earth to love was given to us by Him.