The Troubled Gadol

Rav Avraham Genechovsky ztz"l was once in a very difficult situation when he was in danger of suffering a significant loss. Yet, he was speaking about it in a detached way. His son asked him if he wasn't troubled by the situation. He responded that he IS bothered. By the following question: What is the Din if someone is מתחייב מיתה by בית דין and then becomes a שוטה. Do we carry out the punishment? On one hand - he is a שוטה and we don't punish שוטה's. On the other hand - when he committed the infraction he was not yet a שוטה. R' Avraham needed proofs from the Gemara and Rishonim. THAT was troubling him.