It seems clear to me that the strategy of JPLS et al is to delay the legal process by appeals and then make the argument that Sean is adapted to his environment and therefore it is not in his best interest to be returned to David. This argument/perspective is reasonable generically and has been codified by the Brazilian courts so far.
at least we know we have a great "ally" that doesn´t agree with that, the Supreme Court Minister Alberto Menezes Direito, but I hope we won´t need to go to STF to have Sean back to US.