In a previous installment, we discussed the great value of the Kaddish recitation for a deceased parent, and how it benefits the parent's soul. The Hida (Rav Haim Yosef David Azulai, 1724-1806) emphasizes in particular the value of the Kaddish recited following the reading of Tehillim. He writes that this Kaddish recitation has the ability to protect a parent's soul from harmful forces in the afterlife.
However, notwithstanding the great importance and value of Kaddish, one must realize that other Misvot, too, bring great benefit to a parent's soul. The Gemara (Sanhedrin 104) teaches, "Bera Mezakeh Abba" – a son brings merit to his father through the observance of Misvot. Elsewhere (Erubin 70), the Gemara states that a son is "Kareh De'abu'ah" – his father's "leg." After one leaves this world, he is no longer capable of performing Misvot, and so he is unable to rise to greater heights in the afterlife – if not for his children, whose Misva observance brings him merit. In this sense, a child is the parent's "leg," enabling the parent to move forward despite being unable to continue fulfilling Misvot.
In particular, besides Kaddish, learning Torah and giving charity in a parent's memory bring immense benefit to the soul.
Additionally, a son benefits his parent's soul by reading the Haftara for the congregation. Many people assume that the Aliya of "Mashlim" is the preferred Aliya to receive in the synagogue, because it comes with the recitation of Kaddish. However, Hacham Ovadia Yosef maintained that Maftir is even greater, because of the special benefits granted to a parent's soul through the reading of the Haftara. Therefore, if a person has the choice between these two Aliyot, then – assuming he is capable of reading the Haftara properly – he should choose the Aliya of Maftir.
The practice in some Ashkenazic communities is that only one person recites Kaddish. There as entire literature in Ashkenazic halachic sources determining the order of precedence when several people wish to recite Kaddish for a departed loved one. Unfortunately, this practice often led to a great deal of strife, as people vied and competed with one another for the privilege of reciting Kaddish, prompting a number of leading Ashkenazic Poskim to adopt the Sephardic model, whereby all who need to recite Kaddish do so together in unison. The Hatam Sofer (Rav Moshe Sofer, Pressburg, 1762-1839) changed the practice in his yeshiva to follow the Sephardic custom in order to avoid strife. And Rav Yaakob Emden (Germany, 1697-1776), in his commentary to the Siddur, writes that he decided to omit the discussion of precedence with regard to Kaddish, because the Sephardic custom, that the people recite Kaddish together, is preferable, as it avoids strife and conflict. The work Yesh Nohalim emphasizes that a person's performance of Misvot is far more beneficial to his parent's soul than his recitation of Kaddish, and his "hair would rise" when he saw conflicts arise among mourners in the synagogue over the Kaddish recitation.
Such conflicts occasionally take place even in Sephardic congregations when two mourners or people observing Yahrtzeit vie for the privilege of leading the service, or for the Aliya of Mashlim. I remember that our great Rabbi, Hacham Baruch Ben-Haim, observed Yahrtzeit on the same day as one of the congregants in his synagogue, Shaare Zion, and each year, he deferred to that congregant. When asked about this practice, he explained that avoiding strife and conflict brings far more benefit to a deceased's soul than leading any part of the service. There is nothing more precious that a person can do to benefit the soul of a parent than to increase peaceful relations among Jews.
People must realize that if leading the service requires anger and instigating strife, then the merits accrued are more than offset by the sins that have been committed. The Arizal taught that anger contaminates the soul, and one must immerse in a Mikveh to cleanse it afterward. Without question, there is no sense whatsoever in becoming angry and initiating a fight out of a desire to bring merit to a parent's soul.
When several people recite Kaddish together, they must ensure to recite it aloud in unison, so as not to confuse the congregation.