I completely agree that is was irresponsible of the owner to spring the mention of seizures on you, and upon return, I'd be having a serious talk with the owner. Totally unacceptable. I have personal experience (owned a dog that dealt with epilepsy) and I can tell you that 4 minutes is a VERY LONG seizure. This dog should be under veterinary care and on some sort of medication. Was it? With every seizure, it affects the brain. Yes, the seizure will pass and there will be a period (called post-ictal stage) where the dog won't behave the same, essentially it's a reboot period for the brain. The first time our dog had a seizure, it growled at us as if we were new and we were invading his territory.

IF meet & greets are skipped in the future, I would highly recommend asking about any medical needs prior to drop off. My three main questions for any dog I think about sitting are: 1) are there any medical conditions? 2) do they do well with kids (I have 3, one being a toddler so very important to me)? And, 3) what are their normal routines.

I am very sorry this was sprung on you. We went through months and months of repeated seizures and I don't wish them on anyone.

Edit to directly answer your questions: Seizures are uncommon but do happen. I would personally still take the dog but I do have personal experience with dog's having seizures so know what to do and/or expect.