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.
Which is better, to pray at a prayer place (Musala) whereas many people pray in it, or at a near by mosque in which a few people perform prayer?
Praying at the mosque that has a bigger number is better so long as the number of praying people at the other mosque permits performing prayers in congregation. And Allah Knows Best.
Is it permissible to donate corneas to Jordan Eye Bank or all the organs via telephone?
All perfect praise be to Allah, The Lord of The Worlds, and may His Peace and Blessings be upon our Prophet Muhammad and upon all of his family and companions.
Corneas donation that is carried out after one's death is permissible by the Board of Iftaa'. Because this procedure is highly sensitive, the donation process
should undergoes to an accredited mechanism. And Allah, The Exalted, Knows Best
Is it permissible to fast on behalf of the dead who died owing missed fast to make up?
His relative should fast on his behalf, and it is permissible for the guardians to give permission to non-relatives of the dead to fast on his behalf as well. And Allah Knows Best.