First, let me say I have your Bentley in my prayers (I have a Yorkie named Bentley too
)
I had a German Shepherd who developed seizures later in life like around 13 years old. Mia's were grand mal seizures. I know you are so very worried but try not to get ahead of the vet's diagnosis. The blood work will give more insight into what is going on.
Please let us know when you get the results back...sending positive thoughts and hugs your way. Dyan