tip: hetalia f/f sort:kudos
There is absolutely no way that a true therapist would disclose information on other patients. It is strictly against their rules of work. They wouldn't even mention the existence of another patient, if they're decent at all.
If you read the rest of the fic, you might find out why the therapist is a bit shady :) plus it's poopy fanfiction so you can't expect too much.