What is the likelihood of diagnosing a person with seizures if his eeg's are normal?

Depends on history: The diagnosis of seizure disorder is mainly based on clinical history. The value of a positive eeg is in classification of seizure type and localization of the seizure focus. A negative or "normal" eeg contributes little to the diagnosis, unless it is done during an attack, in which case the diagnosis of pseudoseizure has to be considered.

Epileptologist: Seizure focus can frequently be difficult to localize in some people. Specialists in the neurology field of seizures are called epileptologists. You should seek one of these locally if possible and if not, you may need to seek a teaching hospital at a medical center to find one who specializes in this disorder.