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and spondylosis are 2 independent condition not related to each other. Cervical spondylosis
wouldn't be causing epilepsy in your father.
It is good to know EEG and brain scans were normal. Most often a cause for epilepsy is not found as in the case of your father. However review of his blood tests may help us rule out any missed causes. Meanwhile it is absolutely important to be regular with antiepileptic medications. He needs to sleep regularly and avoid fasting. Lack of sleep and skipping meals can induce seizures which is not good.
Meet a neurologist
if you haven't met yet to know more about your father's condition.
Hope this helps.
Wish you good health.