What should one who doubts the validity of his ablution and performs it frequently do?
Whoever doubts the validity of his ablution after finishing it, his ablution is valid. This is because the default is the validity of the ablution, and because doubt after finishing an act of worship doesn`t affect its validity. And Allah the Almighty knows best.
Is Zakah (obligatory charity) due on the items used in the trading process such as: cars , shops etc..?
No Zakah is due on equipments used in the trading process such as cars and the like.
Is the son of the sister by breastfeeding considered a mahram in Islam, and is it permissible for a woman to go for Hajj with him?
Everything that is prohibited by lineage is also prohibited by breastfeeding. The son of the sister by breastfeeding is considered a mahram, just like the son of the sister by blood, and it is permissible for him to be her mahram for Hajj and Umrah. And Allah Knows Best.
What is the ruling on the follower (*maʾmūm*) reciting Sūrat al-Fātiḥah behind the imam?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
In our school of Islamic thought, the Shāfiʿī school, reciting al-Fātiḥah is obligatory in every rakʿah of the prayer for the imam, the follower (maʾmūm), and the one praying individually (munfarid), because it is one of the pillars (arkān) of the prayer. Whoever does not perform it, his prayer is invalid, whether the prayer is silent (sirriyyah) or audible (jahriyyah), based on the saying of the Prophet (peace and blessings be upon him): “The prayer of the one who does not recite the Opening of the Book (Fātiḥat al-Kitāb) is invalid.” Agreed upon.
It is stated in ʿUmdat al-Sālik, one of the books of the Shāfiʿī school: “He recites al-Fātiḥah in every rakʿah, whether he is the imam, the follower, or the individual worshipper.”
The jurists of the other schools hold a different opinion, which was previously explained in Fatwa no. (
3169); please refer to it. And Allah Almighty knows best.