just to add that of course she should see a doc as it could be a number of harmless things, not all of which clear up with antifungal medication;and the doc will know which it is and what to prescribe. For ladies of a certain age, itchy nether regions can also be a first symptom of diabetes, again easily controlled but needs addressing by a visit to the doc.
If she REALLY REALLY won't however then Canestan antifungal treatment for nether regions is available at the chemist, either an oral tablet and nether region cream or a pessary and nether region cream do not confuse the two lol. Canestan also do an athlete's foot treatment, don't confuse that one either.