Epilepsy in dogs is pretty much the same as in people. When a seizure occurs, try to remain calm. There is nothing you can do to stop it. If the dog is near something like a piece of furniture that he might crash into, move the furniture. Do NOT try to put anything into his mouth. It is a myth that dogs (or people) will swallow their tongues during a seizure, and you will only get bitten severely for your efforts. Certainly, if the dog is near water - like a pool or a pond - you'll need to get him away from that area or he'll drown.
Once the seizure is over, it can take quite some time for the dog to return to normal. It really takes it out of them physically, so just keep him quiet and let him come back on his own.
Your vet will appreciate you documenting when each seizure occurs, what time of day, and how long each seizure lasts. If this becomes a continuing problem, the timing of the seizures will determine the timing of giving medication. Phenobarbital is the first line of defense in preventing seizures. Some dogs may have one or two seizures, and never have another. You just never know. Keeping your rotty healthy in all other respects is essential. Any kind of stress, be it mental or physical, can set off seizures if the epilepsy is bad enough.
Epilepsy is certainly treatable and not a death sentence at all. I know how awful it is to witness a seizure, but your dog is not going to die because of it. My neighbor has a lab who developed severe epilepsy shortly after he adopted the dog at 2 years of age. Even with meds, he seizes roughly once every 2 months, but it's a big improvement from one a week. Everyone in the neighborhood knows about it and knows what to do (and what not to do) if he has one. This dog's life is in no way impaired due to having epilepsy. He goes camping, floats down the river in a tube, swims in lakes and pools... his owner even had to pull him out of the lake once when he had a seizure.
So yes, your dog can certainly have a completely normal life if he continues to have seizures. Just keep your vet informed and keep up with meds if necessary.
Certain breeds are more prone to seizures. My sister-in-law has a golden lab that has them. The vet told them if he had more than 3 in 5 months to bring him in for medication. You will have to have him checked to see if it is hereditary or a problem like a tumor or brain injury from abuse.Best wishes to the both of you, it is so scary to see them have one.