What is the ruling of Islamic law concerning the validity of a marriage contract concluded between a young man and his paternal cousin without the knowledge or approval of their families, especially after the families later rejected the idea? And is the contract considered binding despite the opposition of the guardian (wali al-amr) and the family?

If the marriage fulfills the conditions of validity, then the contract is sound, and the retraction of the girl's guardian and family does not affect it, unless the woman does not accept, in which case she has the right to demand annulment. It is advised to address the problem wisely, such as through khul' (divorce at the wife's instance) in exchange for waiving half of the dowry, or divorce, especially with the rejection of the parents from both sides, due to the difficulty of maintaining marital life in such a case.