I'm so sorry! I don't know what to tell you. We did have a puppy that had liver shunt, but they did not catch it in time. However, I have heard MANY very successful cases where everything turned out perfectly in the end! It's great that his levels were normal! All I can say is to follow ANY advice your vet gave you, and keep on top of him and if you see any symptoms of anything that doesn't seem "normal" to you, get him checked out. You may also want to research epilepsy and liver shunt to learn what you may have to do in the future and everything to ensure that he has a normal happy life.
Best of luck to you! You are bound to find TONSS of information on those problems here.