8 year old son with migraines or seizures occurs every 4-5 weeks

My son has had monthly migraine headaches since he was about 6. Migraines run in the family and both his pediatrician and a Neurologist were adamant that this is what they were. He would wake up complaining of stomach pain, not want to eat, sensitive to light, and didn't want anyone talking near him. We would close up the house, he would nap and eventually the headache pain would start -usually on the left side of his head and he would cry. Sometimes he would throw up. These migraines occured exactly every 27-28days. I could pinpoint it on the calendar which day they would happen. About a year ago he woke up with the same complaints although this time he had what I called an "episode" he acted confused and when he stood up and he had urinated.  It was odd and something that had never happened. A few hours later he got his typical migraine headache and his neurologist said it was possibly an aura. Migraines can apparently cause all sorts of odd things. However now this "odd" behavior has continued. With all the research I have done -I would say he definitely has symptoms that appear to be typical of a seizure. Although they still occur  with that regular pattern of 28 days or it skips completely. 

He has 2 types of episodes:  

#1 He will complain of stomach ache and mild headache. I can literally hear his stomach rumbling then all of a sudden he gets chilled, his heart rate increases and he starts sweating profusely and loses his bladder. He will typically fall asleep and this will reoccur within a couple of hours. -My research says possibly autonomic seizure/abdominal epilepsy/simple partial seizure.

OR

#2 He will complain of stomach ache, nausea and headache on the left side of his head. He will drift in and out of sleep - complains of lights, noise. Won't eat all day. I will catch him zoned out and if I start to talk to him he repetively swallows or pick at his clothes. Lasts for about 30seconds, falls asleep and wakes up crying because his head hurts so bad. 

He has had 1 eeg recently which was abnormal. The neurologist said he has focal and generalized discharges. (I have no idea what this means) -she said she was surprised that they were not in the occipital region which is where she suspected to see the abnormality. (I am not sure what that means either). She has referred us for an MRI - and suggested that he start on Valproic Acid to treat. Which is apparently used for both seizures and migraines. He is developmentally normal - no issues in school, no brain trauma, accidents or birth trauma - all of which was asked at his eval. I am hesitant to start a medication like this with potential side effects for something that occurs so infrequently and what seems to be mild. On the other hand I would hate for something like incontience to happen at school.

I am curious if anyone has any similarities. I can't find much information out there about regularly occuring or patterned or cyclical type seizures except for the menstrual type. I have also read alot about migralepsy. The Neurologist didn't have much to say about that -or that its not typical. He is on no medications other than I started him on Butterbur/petadolex - which is an herbal supplement for migraines. After starting that he went 13 weeks without a headache but now we have settled back into a 5 week pattern. 

His blood work was considered normal although at the very low end of normal for potassium and iron. Also his BUN showed that he was slightly dehydrated. All of these things I know can be a trigger for things like seizures and migraines. I was curious if anyone has supplemented with potassium, magnesium and iron and had good results?

Any advice or thoughts would be so appreciated. Thank you.