Hey, epileptic here (bilateral - mostly left - temporal lobe and some frontal lobe).
About alcohol, I quit drinking the moment I started my therapy (Keppra then, Tegretol now, luckily), 2 years ago now.
Alcohol should be avoided. I avoid it at all costs, it doesn't matter if it's close to medication time or not, I won't even touch a cake that has some alcohol in it. My neurologist told me he never forbade me from drinking, he encouraged me to try once, a small light beer during a meal... well, I did try, I had a pizza and a Budweiser, and ended up feeling the hungover for 3 days, this happened more than one year ago, so no, I'll avoid even a sip of alcohol.
Now, about communion, I was raised catholic, but they never serve wine during communion, the only time this happened was during my first communion, when the priest dipped half of the sacramental bread (which is small to begin with) into red wine. Never happened again. I haven't been going to church for 26 years, but I attended ceremonies, and never saw wine being served to people.
So, what's my answer? Consult with your neurologist. Maybe, just a sip of wine, away from your medication time, won't hurt, but maybe it does, who knows; I know it can sound as a silly question, but anticonvulsants are not to be messed with. Or ask the church whether they're using non-alcoholic wine.
If you need support, reply, I know anticonvulsants can be a pain and a diagnosis of epilepsy can be a lot to take in.