The following sentence appears in a syllabus of a decision of the United States Court of Appeals for the 9th Circuit (at page 3):
The panel affirmed the district court’s dismissal of Longoria’s family-members’ § 1983 claims. The panel held that only Longoria’s estate could bring a § 1983 for the violation of his Fourth Amendment rights; his family members had no standing to sue on their own behalves.
My question relates to the correctness of the word in bold faced type in that sentence. I would have written that sentence: " . . . ; no family member of Longoria had standing to sue on his or her behalf." And, I have never seen the word "behalves" used in writing as a plural of "behalf."
Is "behalves" a recognized plural of behalf in a context like the sentence quoted above?