The whey in Molkosan is digested by a lactic bacteria (casei lactobacillus) until there is no more lactose or casein in the product. This makes it very safe for those with intolerances because usually they are reacting to one of those.
In cases of allergies it can be a little bit more difficult to predict how you will react (are you allergic to something else in the milk that is not digested?
Since your allergy is causing epileptic seizures I would not take any chances and I would avoid taking it unless your skin can be used to predict your reaction. In some people with allergies, if you put a bit of the food on a small portion of skin (ex. on your hand) the skin will react and become red and itchy in presence of allergies..