The annual appeasement that is prescribed for departed souls, as per Hindu Scriptures, is known as Varshika Shradha. It is a symbol of repaying debts of the departed sould, remembrance of the person, and soliciting posive and favourable energy from them. This is also the duty of the decendants of the dead people, as a symbol of gratitude, honor and worship, in the same manner as done to gods.
By performing this Shradha, our ancestors’ souls will be appeased, and is like a re-qualification of the decendant to remain in that position. It is this action that will ensure these souls (or Atmas) remain in a plane away from Hell. It is also said that these rituals for the departed is more important than even worshipping god, since duty reigns higher than love for god. Therefore, these rituals are performed by sons, brothers, son-in-laws, and such immediate family members of the departed, on an yearly basis, to sate the departed souls and to usher in their blessings, favourable and positive influences, as as well as perform the inherited duty of the kith and kin.