Insurance after the military

Ok, so DW and I have been talking about insurance. Does anyone know of a case where dependents have left the military insurance set up and then been rejected coverage, due to pre-existing condition?
An example- Colton with his seizures, could be considered just that, and we are worried about it. The military excepts all, no matter what, but it isn't that easy the other direction.

I just wanted to see if anyone has heard of, or knows anyone that has been through it. We have much to long in the service to really get worried about it today, but it lingers on the horizon.