Is it permissible for a sister to marry her brother's friend, who resides in America, with the intention of divorcing him after travel, in order to facilitate obtaining a visa and joining her brother?

It is not permissible to marry temporarily by agreement of both parties, whether the duration is long or short, known or unknown, because it resembles nikah al-mut'ah, which is forbidden by consensus. An exception to this is one who marries with the intention of divorce but does not mention it to the wife or her guardian; this is permissible according to most scholars. Since the woman's guardian and the suitor agreed to limit the duration of the marriage, this nikah is not permissible. It should be noted that a Muslim's travel and residence in lands of disbelief without necessity entails great harms.