If it appears that the person examined has a mental illness and is not a resident of the Commonwealth, the same proceedings shall be had with regard to him as if he were a resident of the Commonwealth, and, if he is admitted to a state facility under these proceedings, a statement of the fact of his nonresidence and of the place of his domicile or residence or from where he came, as far as known, shall accompany any petition respecting him. The Commissioner shall, as soon as practicable, cause him to be returned to his family or friends, if known, or the proper authorities of the state or country from which he came, if ascertained and such return is deemed expedient by the Commissioner.