I do not know of a drug, vitamin, or mineral, herb, or other supplement that
will change anatomy.

Homeopathic in this instance is not really the term you are searching for, I believe. Homeopathic remedies have nothing basically in them, they are diluted up to a million times, and the belief in them is mostly their result. Some newer
versions have a tiny bit of active ingredient, but most are highly dilute.

Use of some things may help with seizures in some people.
The old epilepsy board had posts about fish oil, flax oil, and some vitamins.
Fish oil is thought to reduce membrane excitibility, and reduce seizures for some. http://www.raysahelian.com/seizure.html
This should be discussed with his doctor, and if your husband uses RX drugs, they needed to be factored in. Folic acid can interfere with some seizure drugs, and increase frequency. It has to be used very carefully.
But response to these are extremely variable, since seizures can come from many causes.

I would caution you to AVOID high doses of Vit A (retinol), not betacarotene
because Vit A may increase intracranial pressure. So even if your husband is
using a multivitamin..check the formula..to see how much Vit A is in there.

I would stay away from herbal products, since they can also be very unpredictable.