My aunt is epileptic & has 2 children. From memory she gave up her license & went off medication to have her kids.
She had them about 18 months apart & didn't breast feed so she could go straight back on her meds after the babies were born. Sorry, I don't know any more than that.

Maybe your sister could ask the specialist receptionist if she can be put on a cancellation waiting list, so she might be able to get a sooner appointment.