What is the ruling of the Shari'ah regarding a young man marrying a girl who studies with him at a co-educational university, whose father refuses to marry her to him, forces her to study in a mixed environment without a mahram, and refuses to communicate with the young man, given the suspicion that the father has a psychological illness? And what should the young man do if the father's guardianship (wilayah) falls away? Is it permissible for him to meet her if the father allows it without witnesses?

You must sever your forbidden relationship with this girl and repent to Allah. Contact her male relatives to complete the marriage, and it is not permissible for you to communicate with her directly. The father's permission for this is a sin and an act of cuckoldry (dayatha), and his guardianship does not fall unless he withholds his daughter [from marriage without valid reason]. If the father withholds, the guardianship transfers to the next in line (such as the uncle). If the uncle marries you off with witnesses, and with offer and acceptance, the marriage is valid. Otherwise, if you cannot convince the father, then leave her and seek someone else.