All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
The marriage contract is among the matters in which it is permissible to appoint someone in proxy, as the Prophet appointed An-Najaachi to act on his behalf in his marriage with Ramlah Bint Abu Sufyaan and this story is well-Known. Therefore, there is no harm in appointing the father, the brother or any other person to act on behalf of the bridegroom in a marriage contract.
Allaah Knows best.