
Hi! I used to have an epileptic dog and I understand completely how very worrying and distressing it is, especially for the owner. If your sister's dog is fitting more than once a month the vet will probably want to try her on phenobarbitone (epiphen) to control them. This isn't an expensive drug, but it can take a few weeks to get the dosage right for each individual dog, and yes, it can make a tremendous difference.
There is a lot of information about canine epilepsy on the net; you'll find the
Phyllis Croft Foundation website of interest, as well as the
Canine Epilepsy website.
Hope this helps.