My cousin is has epilepsy. I asked her about it and this is her response.
"As an adult I've never had trouble with my pre-existing condition. It seems to get folded right in with no questions asked and no outrageous premiums. Don't know what the situation is like if you're looking into establishing your own health care system or trying to get simple family insurance.
This is just a guess but it may depend on the type of epilepsy her daughter has. If it is mild and controlled insurance shouldn't be that much of a problem. I would also suggest that she contact the American Epilepsy Society:
http://www.aesnet.org/ or
www.epilepsy.com
"