Is it necessary to renew the marriage contract in the presence of an official power of attorney from the wife's brother to complete the marriage, and must the parties be informed beforehand?

It is permissible for the woman's guardian to delegate someone else to perform the marriage contract for his ward, provided that the proxy is qualified for guardianship. If the代理 is invalid due to the absence of a designated proxy, then the marriage is not valid and the contract must be renewed. However, if the closest brother designates a specific person who is fit for proxy, and the contract is concluded in the presence of two witnesses, then the proxy is valid and the contract is valid, and there is no need to renew it.