No child admitted to the Scotland School for Veterans' Children shall be discharged therefrom, or leave the same, or be taken therefrom by any person, except on order of the board of trustees. In discharging a child from the school, or in permitting a child to leave or be taken from the school, the board of trustees shall be governed by the best interests of the child or the best interests of the other children in the school, as the case may be.