When a social services official removes a child pursuant to this part, such official shall place such child with his or her minor siblings or half-siblings who have been or are being remanded to or placed in the care and custody of such official unless, in the judgment of such official, such placement is contrary to the best interests of the children. Placement with siblings or half-siblings shall be presumptively in the child’s best interests unless such placement would be contrary to the child’s health, safety, or welfare. If such placement is not immediately available at the time of the removal of the child, such official shall provide or arrange for the provision of such placement within thirty days.