Oh I am so so sorry to hear that
Our late Westie began to seize in March this year (once a week or so, and they weren't bad really. As time went on he Seized every two-three weeks or so and the time frame was less and less and he recovered much quicker). He passed away of old age (16 years) in Aug. I'm glad we didn't PTS him in March as we had another wonderful 5 months with him.
Keep fighting. And, it may sound silly to some, but do some Preying. I did.
Let us know how he gets on.