We're already talking to a lawyer and a strong case can be made for discrimination.
As the others have said, you have not yet given enough facts for a discrimination claim. Is it possible? Maybe. If the epilepsy is completly controlled by the "medication" (This is a *prescribed* medication, right? One you get at a normal pharmacy and not one where all you have is a written recommendation. If so, all bets are off. There is not a clear decision on the matter and, as I'll explain later, that would doom your case.) you have an argument you are fit parents. But, now what?
Arguendo, CPS erred. You are still a long way from any *compensation* for your *injury*. Such things tend to compensate for harm and punitives are rare. You will need to articulate, in dollars, how much you were hurt. Also, you have the problem of qualified immunity. You will need to prove (Essentally, it's complex and why you would need a lawyer.) that there is no way any reasonable CPS worker or department would act as they have or the suit would get kicked at the pleading stage. Not that *these* people *wanted* to hurt you (which is why the judge is irrelevant in the first portion of the suit), but that no reasonable person with like training or experience could believe they were following the law. That means you pretty much need a California court case(s) which prevents them from removing the children for the reasons they stated or for any reason which can be stated from the facts which were within their knowledge at the time of each decision.
With a quick search (don't rely on it, it just used a key word or two), all I found that epilepsy which is not *completely* controlled has been allowed as a reason when there is danger to the child--perhaps because of a prior incident. So, your hurdle will be to claim the disability is completely controlled to even make it to step two.
The end result, as mentioned by others, is that you have high hurdles and absent many more facts, zero chance at punitives. Perhaps you might contract a national epilepsy organization who may help you with your case (if the facts are right) so you can make new law. New law is very expensive, long running and there is not a big money payoff at the end. The end is that future people in the situation you claim may have an easier time proving up discrimination in like circumstances.