92:9 If someone cooks on Shabbos for a sick person, a healthy person is not permitted to eat it on Shabbos. After Shabbos, however, a healthy person may eat it immediately so long as it was cooked by a Jew. (Mishnah Brurah 318:14 says this is true even if it was cooked by a non-Jew; since he cooked it permissibly, the rule of bishul akum does not apply.)
92:10 If a person is being forced to violate a mitvah, even if it is a serious sin, we do not override Shabbos to save him from committing the sin (unless it is one of the three cardinal sins of murder, idolatry and adulterous or incestuous sexual relationships – Mishnah Brurah 328:31).
However, if he is being forced to give up Judaism and become separated from the Jewish people, even if it is a young boy or girl, everyone is required to try to save him even if it means disregarding a Biblical Shabbos prohibition, just like we are obliged to override Shabbos for a dangerously sick person. The Torah says, "The children of Israel shall keep the Sabbath" (Exodus 31:16) and the Sages explain that we should violate one Shabbos in order to enable that many more be observed. Even if we are not sure that our efforts will be helpful, we are obligated to override Shabbos in order to try everything possible, just as we would in the case of possible physical danger. However, if someone is intentionally looking to separate himself from the Jewish community, we do not override Biblical Shabbos prohibitions for him because when it comes to a willful sinner, we do not tell people to sin for their benefit. When it comes to Rabbinic prohibitions, however, such as traveling beyond the Shabbos limit, riding on a horse, traveling in a wagon, or handling money, one may do so in order to save him.