My sister's dog had a problem with seizures and has successfully treated them (he hasn't had one in two years). I emailed her and asked how she has treated him, so you might want to check back here later.
EDIT: Here's what she said. And FYI, she's not the type of person much given to alternative/holistic health care. "First, I went to a vet who is licensed to practice Eastern Vet Medicine and she prescribed some Chinese herbs, which he has been on ever since. Then, we put him on CBD oil. And I am really careful not to give him anything with Rosemary or Rosemary extract, that can trigger seizures. Finally, if he has a seizure, he gets Haggen Daz vanilla ice cream right after to raise his blood sure level, which gets depleted from a seizure."
I remember from our previous conversation about it that she said that a lot of dog treats have Rosemary extract in them.