Regarding supplicating for parents in the salaah and passing the reward of reading the Qur.aan or doing the tawaaf to them
Question: They say that supplicating for the parents in the obligatory prayers is not permissible and nor is passing over to them the reward for completing the Qur.aan or the tawaaf.
Response: There is no harm in supplicating in the prayer either for oneself of for one's parents (or other than them), rather this is legislated. The Prophet (sal-Allaahu `alayhe wa sallam) said: ((The closest a servant is to his Lord is when he is in sujood, so increase in making the supplication (in it))) - narrated by Muslim.
And he (sal-Allaahu `alayhe wa sallam) said: ((As for the rukoo', then magnify the Lord (in it), and as for the sujood then strive in making the supplication (in it), for it is worthy of being responded to)) - also narrated by Muslim.
And in the two Saheehs' (of Imaam al-Bukhaaree and Imaam Muslim), on the authority of Ibn Mas'ood (radhi-yallaahu 'anhu), that when the Prophet (sal-Allaahu `alayhe wa sallam) taught him the tashahhud, he said: ((...then choose a supplication which pleases you and supplicate (with it))).
And in another narration: ((...then choose from that which you desire)).
What is implied here is before the tasleem, so if he supplicates in the sujood or at the end of the prayer, for himself, his parents or the Muslims, there is no harm (in this) for what is mentioned of the generalness of these ahaadeeth and other than them. As for passing the reward for reciting (the Qur.aan) or making tawaaf for one's parents or other than them from the Muslims, then this is an issue where there is a difference of opinion amongst the scholars. That which is better, is to leave this since no evidence exists for its permissibility. Acts of worship are permanently stipulated, so nothing is to be practised unless legislated by the Sharee'ah, for the Prophet (sal-Allaahu `alayhe wa sallam) said:
((Anyone who introduces something into this matter of ours (i.e. Islaam), that which is not from it, will have it rejected)) - this (narration) is agreed upon (by both Imaam al-Bukhaaree and Imaam Muslim).
And in another narration: ((Anyone who does an act which is not in agreement with us, then he will have it rejected)) - narrated by Muslim.
And Allaah is the Expounder of Success.
Shaykh Ibn Baaz
al-Bid'u wal-Muhdathaat wa maa laa Asla lahu - Page 382;
Mujallah al-Buhooth al-Islaamiyyah - Volume 46, Page 198
Taken from fatwa-online.com