In marriage, you must get two approvals for it to move on; the approval and consent of the guardian and the approval of the bride to be!
If the father doesn’t give his approval, this marriage can’t take place except in one condition and that is when the father is oppressive and is not qualified to choose the best for his daughter! This is recognized when he rejected a number of good proposals or insisted on accepting bad proposals from sinful Muslims who pay no weight to Islam!
In this case, she can complain to the Muslim judge who would look into her case and decide whether to move her guardianship from her father to a brother or a grandfather or to become her guardian himself!