Hello falldc,
I'm sorry to hear what has happened for your husband and his seizure. I don't know that it is "common" but it certainly can occur. In fact, there
have been posts from a few members in the past on the TBI/PCS forum who began to experience seizures after head injury.
You'd be best to ask on the
Traumatic Brain Injury & Post Concussion Syndrome Forum
You could also do a forum search there using the Search feature if you want. Choose "advanced search" function and choose the TBI/PCS forum.
http://neurotalk.psychcentral.com/search.php