Is it permissible to wear pants after the father swore and prayed for his daughter's death if she were to wear them?

Obedience to a father is obligatory in matters that are permissible [in Islam], meaning those that are not forbidden by شرع (Islamic law), do not impose excessive hardship on the child, and bring benefit to the child or the parents. This obligation is emphasized if the father has sworn an oath and his anger is the reason for the command, based on the hadith: "The pleasure of Allah is in the pleasure of the parents, and the displeasure of Allah is in the displeasure of the parents." It is also recommended to fulfill an oath, as the Prophet (peace be upon him) said: "The Messenger of Allah (peace be upon him) commanded us with seven things: ... and fulfilling the oath of one who swears."

Accordingly, it is obligatory for the daughter to obey her father in abandoning that which he swore she must abandon.

If the father regrets and wishes to permit his daughter to do what he forbade her from, and if her action adheres to Islamic regulations, he can expiate his oath and allow her to do so, based on the saying of the Prophet (peace be upon him): "Whoever swears an oath and then sees something else as better than it, let him expiate his oath." Expiation is only required if he swore that she should not wear it without any condition. However, if he swore that she should not wear it only without his knowledge, then no expiation is due if she wears it after he becomes aware.