Answer
Wa `alaykum as-salamu wa rahmatullahi wa barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Dear brother, we commend your eagerness to become well acquainted with the teachings of Islam, which is the way Allah has chosen for the welfare of His servants.
Divorce is a man’s right that can be done by himself or by a person he has deputized to do it. As for the intention of the husband to only divorce his wife for the sake of getting the needed papers to marry someone else for the nationality, it is not taken into consideration. The divorce is valid.
Islam never takes marriage and divorce lightly. This is clear in the Hadith in which the Prophet (peace and blessings be upon him) says that there are three matters which must be taken seriously, whether they are said seriously or humorously; these are marriage, divorce and freeing of a slave.
In response to your question, Sheikh Faysal Mawlawi, Deputy Chairman of the European Council for Fatwa and Research, states,
A husband has the right to deputize someone to divorce his wife on his behalf, and then the divorce takes place as if uttered by the husband himself.
Accordingly, if your father went to the court and divorced your wife on your behalf, then the divorce becomes valid no matter what your intention was.
Then the known rulings of divorce apply to that divorce. If it’s the first or second time of divorce, you can return your wife back to the marital life before the expiry of the `iddah (waiting period). However, if the `iddah expires, you cannot have her back unless you conclude a new valid marriage contract.
If it’s the third time of divorce, then you cannot remarry her unless she marries another man in a valid marriage. If the second husband divorces her or dies, then you can remarry her after the expiry of her `iddah.
Allah Almighty knows best.