Obedience To One’s Deceased Parents
Sayyiduna Abu Usaid Malik bin Rabi'ah As-Sa'idi Radhiyallahu Anhu reports: We were sitting with Messenger of Allah Sallallahu Alayhi wa Sallam when a man of Banu Salamah came to him and asked, "O Messenger of Allah! Does there remain any form of obedience which I may show to my parents after their death?" He Sallallahu Alayhi wa Sallam replied, "Yes, to pray for them, to supplicate for their forgiveness, to fulfill their promises after their death, to maintain the ties of kinship which cannot be maintained except through them, and honour their friends." [Abu Dawud]
When a parent passes away remember that you have begun a new phase of birr (dutifulness) to that parent.
Birr after death is the truest and most sincere forms of birr because birr during their lifetime could be tainted with doing for show, or being polite (as opposed to sincere) and expecting praise from the parents or others. As for after their death, then only Allah hears and sees you.
A deceased parent is in greater need of his/her children - even more than when the parent was alive. What children do for the parents during the parent's lifetime is for the worldly needs.
But after death only Allah knows what good and bad is in store for the deceased in the grave.
Dua'a for rahmah (mercy) and asking Allah to shower the deceased with His mercy is invaluable for the deceased.
Through the child's Dua, Allah - through His grace and mercy - enlightens the grave removing the darkness and expands the grave thus removing the suffering. And Allah makes the grave a garden from the gardens of Paradise.
Therefore, always remember your deceased parent/s, and always ask Allah to shower them with His mercy, enlighten their grave and expand it.
For example as you are about have a meal, think about the many wonderful meals your mother had prepared for you and how she took care of you all your life. Your heart will surely soften and at that point, let it drive you to offer a similar meal to an orphan, widow, divorced or needy person on behalf of your deceased parent/s and asking of Allah to reward them for it. Give charity on their behalf, recalling the many favours they did for you.
Never forget parents. Irrespective of how harsh they may have been with you, only Allah knows the love they had in their hearts for you.
Give charity on their behalf privately, wipe away the tears of orphans, widows and divorced (through charity) on behalf of your parents, quench the thirst of the thirsty on their behalf. (for example by having a well dug.)
Go out of your way to be the best child to your parents for they have sacrificed much to raise you.
This is the Dua'a mentioned in the Quran for one’s parents:
رَّبِّ ارْحَمْهُمَا كَمَا رَبَّيَانِي صَغِيرًا
Rabb-ir-ham-huma kama rabbayaani sagheera
My Lord, Bestow thy mercy on my parent/s as they cherished and raised me in my childhood.
Lastly, let us teach our children this Dua'a for one day we all shall also need it.