Q. An individual used to be religious, went off the derech, ending up marrying a non-Jew. This individual is definitely not a mumar l’hachis. Now he is not well. Is it proper to daven for his health, since his continuous existence is b’issur? In addition this might constitute having mercy on wicked people which the Orchos Tzadikim writes is worse than cruelty. When such a person dies is there shiva for him?

A. See question 647 where we wrote; no shiva and mourning are observed for the ones who willfully abandoned the Jewish community, converted to another religion or intermarried with Gentiles, ( Shulchan Aruch Y.D. 345: 5,) unless they openly repented before they died. (Remoh Y.D. 340: 5, Chochmas Odom 156: 3)
Although today it is customary to mourn for non-observant relatives since they are considered “Tinok Shenisbah” or being unknowingly or non-consciously nonreligious, however, intermarrying as converting to another religion are extreme acts that almost everyone would accept as willful and deliberate. (Tzitz Eliezer 13: 94, Yalkut Yosef ”“ Avelus 14: 13, Shevet Halevy Y.D. 1: 165)
Some Poskim mention observing avelus for one hour, (Yalkut Yosef Avelus p. 302, Ma’ayan Omer 84) however, they stress that this may depend on unusual circumstances and a Posek should be consulted in every case.Besides this last Halacha, Horav Shlomo Miller’s Shlit”a opinion is similar.
On question 646 in regards to kevura we wrote; Horav Shlomo Miller’s Shlit”a opinion is that he should be buried in a Kever Yisroel, albeit in the established designated section.
The Rov added that one should always pray for the prompt and true teshuva specially of this type of mumarim, as they can always return.

Rabbi A. Bartfeld as advised by Horav Shlomo Miller Shlit’a