After death, the son says… Kaddish, and through this, he saves his father from the judgment of Gehinnom (Purgatory).

"At the moment when my son said Kaddish, they tore up my decree of (bad) judgment entirely." So said one particular deceased person to Rabbi Zemira.

If the children are unable to recite Kaddish themselves, they can arrange for a proxy to do so. This is a great comfort and merit for the departed soul.

“Yizkor must be recited for a deceased parent. In addition, Yizkor may also be recited for all deceased relatives and friends, if the person reciting Yizkor has a deceased parent.”

“Great is charity, which removes one from the judgment of Gehinnom (Purgatory)… The main point of the Remembrance of Souls is to give charity in the merit of the departed. This is specifically true if it is a son donating charity in the merit of his parents.”

…From here we learn that donations that the living give in the merit of the deceased, have a great benefit for the deceased. And particularly (this is true) when the son donates in their merit.

“The sages of the Midrash attach great significance to the daily recital of Kaddish by the children of the dear departed. This recital of the praises of G-d redeems their parents from the punishments of Gehinnom (purgatory) and elevates them in Heaven.”