1,315. Relatives Not at the Funeral

204:3 In a place where the deceased are sent to another city for burial and mourners at home don't know when he was buried, they start mourning as soon as people return from the funeral, counting both shiva and shloshim from then. (Shiva and shloshim are, respectively, the seven-day and thirty-day periods of mourning in different intensities.) Those who accompany the deceased to the cemetery count these things from the burial. Some authorities maintain that if the head of the household accompanied the deceased to the cemetery, then those who remained behind also start counting from the burial. They estimate according to their calculations when the deceased would have been buried and they start their mourning period. We follow the stringent position and act as the head of the household, so those who stayed behind also count their mourning from the burial. However, if the head of the household remained home, then those who accompanied the deceased don't follow his lead; rather, they count from the burial.

204:4 If someone drowned or was killed by idolators and his grave has not been found, then so long as we haven't given up looking for him, the relatives do not observe aninus or aveilus (forms of mourning); they are even permitted to engage in marital relations. Once they give up looking, then they start their mourning. If the body is found after the mourning period and they are obligated to bury him, they don't observe any additional mourning unless it was one's parent, in which case one must tear his garments.

If a married man drowned, leaving a situation where his wife can't remarry (out of doubt as to whether he is alive or dead), he is not mourned, nor is kaddish recited for him. Nevertheless, we try to give his soul some peace by leading the prayer service, reading the haftarah, bentching with a zimmun (a quorum of three), giving charity, and studying Torah, or hiring someone to learn Torah in the deceased's merit.