My Grandson Has Been On The Ketogenic Diet For Four

My grandson has been on the ketogenic diet for four years and his seizure disorder appears to be under control now. He began having seizures just about at his third birthday; until then he was developing normally. Medication alone was not able to control the seizures so after several months of trials of medication, he was placed on the ketogenic diet. He cooperated beautifully throughout this ordeal. He is gradually being 'weaned' off successfully from the ketogenic diet and continues to take some medication which is monitored by his neurologist, Dr. Oscar Devinsky. He is now 7 years old and attends a special class (because he has some learning delays, but he is advancing quite well in his academics) and gets extensive speech and language therapy, OT and PT and is reported to be making very notable progress in these areas as well. In your opinion, can the time come that we could feel secure that he will be seizure free and catch up cognitively.