Is the marriage of a virgin valid with the father's consent if he is under duress, and he is originally unwilling, especially if the reason for his refusal is his daughter's marriage to a married man?

If the suitor is pleasing in his religion and character, the father should agree, based on the words of the Prophet, peace and blessings be upon him: "If someone whose religion and character you approve of proposes to your daughter, then marry her to him. If you do not do so, there will be tribulation on earth and widespread corruption." His being married to another woman does not matter as long as justice is expected from him. The woman may use legitimate stratagems to convince her father, and if he insists on refusing, she may refer her case to a judge.