Ruling on adding a rak'ah to the prayer and dedicating its reward to the deceased

Question:
He has two questions in his letter. He says: Is it permissible for me to pray an extra rak'ah in every obligatory prayer for my father, and to perform Hajj on his behalf, given that he has passed away?

Answer:
In the name of Allah, the Most Gracious, the Most Merciful.
Praise be to Allah, and may Allah send prayers and peace upon the Messenger of Allah, and upon his family and his Companions, and upon those who follow his guidance. As for what follows:
Allah (Exalted and Majestic is He) has prescribed for the servants to be dutiful to their parents and to do good to them through charity, supplication, and other types of good that benefit parents whether they are alive or dead.
However, praying for one's parents is not prescribed, and no text has come regarding it. Therefore, a child does not pray for his father, but rather he supplicates for him and gives charity on his behalf. He performs Hajj on his behalf if he is dead, or if he is unable to perform Hajj due to old age or an illness that is not expected to end, or the like.
As for his praying on his behalf, this is not prescribed. But he should supplicate for him, give charity on his behalf, and perform Hajj on his behalf if he is dead or unable. Likewise, all other types of good that benefit him, such as sacrificing an animal on his behalf, performing 'Umrah on his behalf, and being kind to his friends and relatives, and the like of these avenues of good. Yes.

The presenter: The listener says: He prays an extra rak'ah in every obligatory prayer on his behalf.

The Shaykh: No, this is not prescribed.

The presenter: Does this affect the validity of the prayer?

The Shaykh: It is not permissible. If he adds a rak'ah to the prayer, he invalidates it. If he prays, for example, five rak'ahs for the midday prayer, with the fifth for his father or his mother, this is invalid. This is an error and a reprehensible innovation. Or if he prays it separately, it is also not permissible. Even if he prays it separately, that is not permissible; because Allah (Glorified and Exalted is He) has not prescribed for us to pray for our fathers, nor for our mothers. So this is reprehensible. The Prophet (peace and blessings be upon him) was asked; a man asked him, saying: "O Messenger of Allah, is there any dutifulness to my parents remaining by which I can be dutiful to them after their death?" The Prophet (peace and blessings be upon him) said: Thus the Prophet (peace and blessings be upon him) clarified.
This includes supplication for them, and the funeral prayer. The funeral prayer and supplication for them; because supplication is called prayer. Allah the Exalted said: [At-Tawbah: 103] meaning: supplicate for them. And prayer for the parents is supplication for them for forgiveness, mercy, and salvation from the Fire, and supplication for them in their lifetime for the multiplication of reward, the acceptance of good deeds, well-being and health, and the like.
: Seeking forgiveness for them. : Carrying out their wills if they bequeathed something that does not contradict the Shari'ah. The child carries out the will, the will of his father; because Allah (Exalted and Majestic is He) has prescribed that for him. And this is part of his helping him in good. So if his father bequeathed something that Allah loves, such as charity, building mosques, sacrificing an animal on his behalf, and the like, then the child carries that out.
As for if he bequeathed something that is not prescribed, the child does not carry it out. If his father bequeathed that he build a mosque on the grave, or build a dome on it, this is a reprehensible innovation. He does not accept this will, nor does he carry it out; because it contradicts the Shari'ah. Likewise, if his father bequeathed that he cut off his relatives, and not speak to his uncle, and not maintain ties with his brothers, this is an invalid will, cutting off family ties. He does not carry it out. But he carries out the lawful wills, such as if he bequeathed that he give charity on his behalf, renovate a mosque for him in accordance with the Shari'ah, sacrifice an animal for him, or perform Hajj for him, there is no harm.
So the point is: he carries out the covenant of his father and his mother if that is something lawful. As for if that contradicts the Shari'ah, then no. And likewise, honoring the friends of his parents, he honors them and does good to them. It has come in the hadith from the Prophet (peace and blessings be upon him) that he said: This is among the most dutiful acts of dutifulness, that he maintains ties with the loved ones of his father, the close friends of his father, and his relatives. And likewise, maintaining family ties that are not maintained except through them, such as doing good to his paternal uncles, to his grandfather, his father's father, to his maternal uncles, his mother's brothers, and the maternal uncles of his grandmothers, and the like. All of this is maintaining ties with the parents. His maintaining ties with the relatives of his parents is maintaining ties with them. Yes.

The presenter: May Allah reward you with good.