Upon receipt of a certificate of an agency of the United States that facilities are available for the care or treatment of any individual confined pursuant to law in any State mental health facility and that such individual is eligible for care or treatment in an institution of the agency, the Department of Mental Health may cause his transfer to the agency of the United States for confinement. Upon effecting the transfer, the court ordering confinement, the legal guardian, spouse and parents or, if none be known, his nearest known relative or friend shall be notified thereof immediately by the Department of Mental Health. No person shall be transferred to an agency of the United States if he be confined pursuant to conviction of any felony or misdemeanor or if he has been acquitted of the charge solely on the ground of mental illness unless prior to transfer the court originally ordering his confinement shall enter an order for transfer after appropriate motion and hearing. Any person transferred as provided in this section to an agency of the United States shall be deemed to be confined by the agency pursuant to the original order of confinement.