What is the ruling on parents preventing their daughter from marrying a competent man whom she feels comfortable with, justifying that with invalid reasons? Do they sin by doing so? And does the father's guardianship fall if he curses the religion?

Whoever intentionally insults Allah the Almighty or the religion of Islam has committed an act of disbelief (kufr) and exited the fold of Islam. Their repentance is accepted if they return. However, it is not sufficient for the one who mocks to merely repent; they must also be disciplined. If the father insults Allah the Almighty, not under duress or while mentally incapacitated, he has exited the fold of Islam. He cannot be a wali (guardian) in marriage for his Muslim daughter until he returns to Islam. If his guardianship falls, it transfers to the next in line. If the father repents and returns to Islam, but then refuses to marry his daughter to a suitable suitor whom she accepts, he is considered a 'aḍil (one who unjustly prevents marriage). If the father's 'aḍl is proven, the daughter may take her case to the Sharia judge, who will order the father to proceed with the marriage. If he refuses, the judge himself will arrange her marriage. The daughter must strive to reform her family and improve its reputation, and distance it from forbidden customs, through supplication and good treatment.