Is it valid for the marriage to take place with the ma'dhun (authorized marriage official) in the presence of only the groom, the bride, and her mother, in the event that the father refuses to marry off his daughter out of greed for money, and there is agreement between the prospective spouses, and the consent of the mother and younger sisters?

If a father prevents his competent daughter from marrying in order to get money from the suitor to pay off his debt, then he is an 'adil (one who obstructs marriage). In this case, the girl can refer her matter to the Sharia judge, who will order her father to marry her off. If the father refuses without a legitimate Sharia excuse, the judge will perform her marriage. It is not permissible for a girl to marry without her guardian's consent, except by order of the judge when the guardian is an 'adil.