So sorry to hear he had another seizure.:( I was just wondering about him the other day since you had not posted lately.
Has your vet added potassium bromide to the therapy yet?
Here's a real good link that I think explains seizure therapy to help the 'owner' to make decisions and be able to discuss it with your vet on what course to take next. Print it out and go over it with your vet.
http://vet.osu.edu/vmc/companion/our-services/neurology-and-neurosurgery/more-epilepsyHope everything works out and you can get the seizures under control. Do 'not' give up until you have exhausted all avenues.
I've seen many dogs with far worse seizures where it did take quite a bit of time adjusting, adding and trying different meds and the outcome was successful in controlling them.
You will be in our prayers. Hang in there. :C