My thoughts are with you and Sequoia. Seazures are scary! I've had a few happen to me and they really are quite taxing on the body.
My parents RB doberman, Blue, had a couple of them later on in his life but they were mild and required no medication. I hope the vet can figure out whats going on, and if medication is needed, I hope they can find one that helps as I have noticed (with me anyhow, not sure about dogs) getting the right one is kind of hit and miss. Hopefully though, it just won't happen again!

*Hugs* to you and Sequoia!!