I'm going to reiterate my concern;
Personally, I see no problem with having the dog itself in the school setting. As long as the learning experience isn't hindered by the dog. I see a problem with exposing little kids to another student who has a seizure several times a week. Like someone else said - it would be traumatizing.
I once witnessed a fellow student have a very mild seizure, and found the situation to be really quite disturbing. And I was 16 years old and in 11th grade at the time. So, I really can't imagine what it would be like for a 7 year old.
Brandon