I751 filed with LIN on 11-Feb-2019.
Fingerprint submitted on 03-Sep-2019
Fingerprint review completed on 04-Sep-2019
Approved on 20-Dec-2019
Card mailed on 26-Dec-2019
N-400 Filed and Receipt for 01-Sep-2020
Biometric Reuse notice on 30-Dec-2020
Interview Scheduled notice on 8-Apr-2021
Interview on 11-May-2021
Oath Ceremony Will Be Scheduled notice on 11-May-2021
Oath Ceremony letter sent on 24-May-2021
Oath Ceremony scheduled for 15-June-2021
Naturalized on 15-June-2021
Submitted passport application via USPS on 15-June-2021
Expedited passport book and card application received by DOS on 22-June-2021with expedited shipping
Passport application approved on 21-July-2021
Passport book expedited shipping on 21-July-2021
Passport book arrived on 24-July-2021
Passport card arrived on 26-July-2021
Currently waiting on NC returned from DOS to arrive
There is another form (I-508) he will need to fill out to explain his A visa status and duties, and to also renounce his diplomatic status.
Similar to what I had to go through.