Is it epilepsy or what is the right medication for treating this?

[questionsask]

Hello my dad is now 78, but he had this for about 10-12 years. Doctors call it as silent seizures or silent epilepsy. He had MRI's and other tests done without any results: "looks normal for his age". He was prescribed Tigretol (carbamazepine)  and the dose was leveled with the blood tests, however he is having episode about once a month. Episode might comprise of series of small episodes, every one of them lasts about 5-20 second, he zones out starts swallowing excessively,  and rubs his fingers on one hand together. Sometimes he does not even realizes that he had an "episode". We also noticed that episodes are normally accompanied with spikes in blood pressure and abnormal amounts of the urination calls. We also noticed that those episodes might (not always) coincide with emotional spikes (after overexcitment, anger, upset).

I know that Carbomazipine is one of the best medications to treat epilepsy, but if it does not removes seizures completely maybe it is not epilepsy. I know people who have epilepsy and they do not have seizures while on meds, or it is very rare occurrence.

My question, if the tests did not show any abnormalities in the brain, can we say it is epilepsy? Why it is not treated by Carbomazepine (may or may not reducing number of episodes) ? What else it could be? How do we treat it to the point of no seizures? I am concern with this situation, because my dad is still trying to stay active and goes for a long bike rides on his own.

Any help or suggestions are appreciated.