In our Muslim community in a town in Pennsylvania, we have only one mosque, and we have a brother who says that wiping over cotton socks for making ablution is invalid. He says that the socks have to meet certain conditions and cotton socks don't satisfy these conditions. I believe that wiping over cotton socks is valid and sometimes I lead the prayer in the mosque. This brother is saying that my prayer is not valid (if I wiped over my cotton socks) as is that of the brothers and sisters who are praying behind me; they all have to repeat their prayers. He always repeats the prayer when he prays in the mosque if he sees the imam is wearing socks, assuming (to be on the safe side) that the imam wiped over his cotton socks. For me, I believe that it is valid to wipe over the socks (I know it because many scholars have said that it is valid), but is he right to repeat his prayer after praying behind me or behind any other brother who wears socks?

Another question, is it true that wiping over cotton socks is invalid according to the most sound and reliable opinion in the four school of jurisprudence?

Please, I need your help in this matter because the brother has stopped coming to the mosque since Ramadan because of this issue.

Wiping over cotton socks is permissible and valid. Many of the eminent companions of the Prophet (saws) even wiped over their ripped socks in the company of the Prophet (saws) himself during the Battle of Dhatu-Riqa`a and he did not prevent them from doing so.

Imam Ibn Taymiyyah is of the opinion that the only condition agreed upon amongst the different juristic schools for the validity of wiping over the socks is that a Muslim should wear them after performing a complete wudu', which includes the washing of both feet. Any other stipulation or condition could easily be argued. It is not a valid condition that the socks be made of leather. Cotton and cloth socks are acceptable too.