I may be a little late, but my son also had seizures from the age of 18 months until the age of 5. He also was in the hospital and given all the neuro tests and nothing conclusive but he was put on the seizure meds. I hated the way they made him lethargic and slow. I took him from doctor to doctor looking for an answer and finally found a gift from God. This doctor took the time to explain that my son had a "Febrile Seizure" condition. Basically his body did not react to a virus or infection in the normal way. So when there was an infection present his temp would go up but his body did not hate a "thermostat" to contol the fever and so when it got too high his brain would seize his body - basically to cool it down. The doctor basically taught me to keep a thermometer in his baby bag and check it once a day. If he did have a fever, I gave him tylenol and kept an eye on the fever. As long as I controlled the fever with meds, tepid baths and and cool cloths he didn't have a seizure. The only times that he seized from 18 months to 5 years was when he got sick during the day at the nursery and they did not realize it, but it wasn't often. Maybe this is what your son has and NOT epilepsy. You are his strongest advocate, make sure they have the right diagnosis! Good luck and God Bless!
BTW - Sounds like you have a great support network -- Have the surgery! It will be a gift to yourself and your family!