Here is the opinion in In re Epik W.:

The EIF excerpt:

In remanding the case, however, we would be remiss if we did not call the Juvenile Court’s attention to the shared agreement that both the Department and the Tribe have in this appeal regarding the Existing Indian Family Doctrine, which was the doctrinal basis upon which the Juvenile Court rejected the ICWA and denied the request for transfer. Indeed, in response to the Tribe’s general advocacy on appeal concerning the invalidity of the Existing Indian Family Doctrine, the Department has specifically disclaimed the vitality of the doctrine, arguing, as we previously noted, that federal regulations “foreclose reliance” on it. Although we have little doubt that the parties still disagree on other issues relevant to a decision to transfer this matter to the tribal court, the shared agreement between the Tribe and the Department regarding the Existing Indian Family Doctrine strongly counsels in favor of the Juvenile Court revisiting the transfer request (as the doctrine was its sole cited basis for denial).

There is only one public brief available, but it’s relevant: