I remember this topic coming up once before and the answers were somewhat inconclusive:
https://www.mobileread.com/forums/showthread.php?t=25078
mostly based on the limited personal experience available. Reasonable hypotheses were there (eg. that e-ink might be suitable over, for instance, a "flickering" screen), but I think I saw mention elsewhere from a seizure sufferer that the "page-turn" quickly gave her a feeling of nausea, which wasn't a good sign (she had gone to a store and tested it). I have little awareness of the triggers for seizures though, and don't know how "personal" they get (I get migraine, where triggers vary greatly for different people, so I'm simply reaching for analogy here, sorry
).
Perhaps if you specify your location (no, I don't mean actual address - just roughly
), some MR members could arrange a "meet-up" in a coffee shop or something where you and your husband could see devices (or at least a device, like the 505) and also see if the page-turn has potential negative consequences?
Otherwise, perhaps since that above thread, MR might have other sufferers who can offer better advice. I wish you well in your search and, for as little as it matters, the same in your husband's health.
Cheers,
Marc