The patient’s identity is not disclosed, so they don’t know the sex.
This is a normal, long time use of the ‘singular they’ which was never a problem for anyone until the ‘pronoun nazis’ started to push their nonsense on us.
What’s wrong with “he or she”? Why should we give up the ability to distinguish plural from singular?
For that matter, why can’t the authorities acknowledge whether this individual is male or female? That’s not sensitive information that would help someone identify the person.