“Extended family member” defined

“ Extended family member ” has the meaning given that term by the law or custom of an Indian child's tribe or, if that meaning cannot be determined, means a person who has attained 18 years of age and who is the Indian child's grandparent, aunt, uncle, brother, sister, sister-in-law, brother-in-law, niece, nephew, first cousin, second cousin, stepparent or another person determined by the Indian child's tribe, clan or band member.