Identity Crisis
Rabbi Ephraim Oshry writes of a halachic query presented to him in the ghetto.

A teenaged Jewish boy hidden with a non-Jewish family converted to Christianity, encouraged by his rescuers. Overcome by agonized regret, he soon returned to the ghetto voluntarily, to rejoin his suffering people. Rabbi Oshry writes:

I was asked whether it was permissible to count this young man in a minyan after he had consented to be baptized, and whether he could be called up to the Torah... Furthermore, he was a kohen, and he wished to go up to the duchan to bless the congregation as his father had taught him... I replied that all these things are permissible.