بسم الله الرحمن الرحيم
Q: The guardian of a woman is about to conclude a marriage contract (giving her away in marriage) however sometimes he prays and at times he abandons it, even though he affirms its obligation, others to whom which the authority can shift to after him, some among them don’t pray at all, and others are unable to attend, so is the marriage contract valid if the first person (mentioned) is the guardian?
A: Yes, this individual is a sinner among the sinful based on the statement of the majority of scholars and it is the more sound position with me. This individual is a sinner among the sinful, however his guardianship is legitimate and the marriage contract is valid.
Translated by Najeeb Al Anjelesi
Source: http://miraath.net/questions.php?cat=51&id=3701