Frankel Family Gets Answers From Rishonim Letzion About Kaddish
At two separate occasions during Shiva, Avraham Frankel, the father of Naftali Frankel HY"D, asked Rishonim Letzion Rav Yitzhak Yosef Shlit"a and Rav Shelomo Moshe Amar Shlit"a the following question:
You have told me that my son is at the top level of Gan Eden. If so, what is the purpose of reciting Kaddish for him? Isn't Kaddish supposed to raise the level of the soul to higher levels? His soul is already on the top level!
Kikar has Rav Yosef's answer:
There are various levels of pleasure in Gan Eden. Reciting Kaddish raises the soul of the departed to a higher level of pleasure.
Ladaat has Rav Amar's answer:
Indeed they are at the highest level, but reciting the Kaddish doesn't only benefit the departed - it benefits the one who recites it as well since it draws kindness and mercy from Above to the one who recites it and his entire family.