Many courts have ruled that the beneficiaries of an immigration application have standing (or the right) to sue for unreasonably delayed decisions or unlawfully denied benefits. However, not all courts agree. So, to be on the safe side and avoid a challenge, it's best to add the US petitioner (usually the sponsoring family member or employer) as a plaintiff in these suits. Some petitioners, such as corporate employers, may not like having their names added to a complaint against the government. One trick to lessen the concern about this is to list the beneficiary's name first on the caption. Because case citations usually include just the first named plaintiff "versus" the first named defendant, employers can minimize public exposure when being listed second. You can also assure the petitioner that retaliation by the government against people who file such suits is virtually unheard of.