What Causes Recurrent Seizures?

My Grandfather (Male aged 66) was at a hospital for a check up today and after walking around the building a few times he finally made it to an open door. After entering, he was placed in a wheel chair and began having reoccurring Seizure like episodes. Although they thought it was seizures at first, they said it was unlikely because his eyes were not rolling. It was noted that the more he had them, the less he was able to speak as they were occurring. He received an MRI and EKG but no tests have come back with abnormalities. I am a worried grandson living over 1500 miles away, so any insight as to possibilities would be greatly appreciated.