Divorce is a man’s right that can be done by the husband himself or the one he deputizes 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 in earnest or jest. These are “marriage, divorce and freeing of a slave.”