Teshuva in Responsa VII
In a Responsum on the Kaddish (no. 203), the Benjamin Ze’ev discusses the following problem. There were two apostates, one murdered by bandits, the other dying in his bed and buried by Christians. The son whose father had
been killed by the bandits recited the Kaddish for him, arguing that his gather had intended to repent but had been killed before he was able to do so. He wished to reserve this privilege for himself, in spite of the claim of the son of the other apostate that he, too, should be allowed to recite Kaddish. I
f the man who had died on his bed had wished to repent there was nothing to have prevented him, since other forced converts were present at the time, the Benjamin Ze’ev rules that the Kaddish is not to be recited for an apostate who dies without repentance since, during his lifetime, he denied the whole of the Torah.