What a shock, Bill! How could lightning strike you twice?
I've never met anyone with AA resulting from seizure medications, but they say that the risk of AA from Tegretol is about 1 in 500,000. Those are long odds but of course you don't want even that low risk if you can avoid it. If Dylan needs medication for epilepsy, is there another anticonvulsant he might take?
Even if there's something wrong in your environment, it's hard to see how it would cause aplastic anemia in one child and epilepsy in another. The
known causes of epilepsy and the
known causes of aplastic anemia don't have much in common. But of course you end up back at "idiopathic", which tells you nothing. I wonder if the health department could tell you if there have been higher-than-average incidences of either disease in your neighborhood.
When my wife got her AA diagnosis (yes, idiopathic), I asked for a CBC test in case we had both been exposed to the same environmental contaminant. My doctor gave me an odd look when I first asked for the test but I explained why I was worried about the possibility, on top of worrying about my wife. (I passed the tests; they didn't find anything wrong with my counts.) So I know exactly how you feel and how strongly you want to find an explanation that makes sense of this.