As far as we can tell, the vet was within the parameters of prescribing this med.
But, from what other vets are telling me, they would have tried other things first.

Word is, this woman vet is allergic to cats, and tends to give them the 'bum's rush'.

The adopter, fortunately, is proactive, and has sent emails to other area vets, asking for an appointment on Monday. She will call when office hours open, I'm sure.
After the adopter raved about this vet, and how 'lucky' she was to 'fall into' her, I was happily surprised that she is willing to give another vet a try. At least she is not stuck on this one person, as being the authority on cats.

Things like this always happen on a Sunday.