Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.
Without the ability to examine and obtain a history, I can not tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.
The concern for your husband passing out is several things. One is post-concussion epilepsy which occurs in up to 5% of patients with closed head injuries. The risk of related to severity of the head injuries such as ever having LOC/amnesia after head injury is of the highest severity. Usually the seizures post-concussion occur within days to weeks to months of the injury and begin to decrease in frequency as time passes. It is usually helpful to obtain an MRI to observe for any focal damage to the brain that may be the source for the seizures. Treatment is usually with a single antiepileptic medication.
Another possibility for the passing out is lightheadedness. Post-concussive patients tend to have episodes of dizziness and imbalance which can lead to passing out. It may be helpful to be seen by a specialist in autonomic testing who performs tilt tables to evaluate for this.
It is important to realize that syncope is a common disorder and could be unrelated to the recurrent head injuries. The workup includes examination of the heart, blood vessels, and nervous system including the autonomic nervous system.
I would recommend that your husband observe seizure precautions. These are precautions to limit harm to himself and to others until the episodes are sorted out.
I don’t have any specific recommendations for who your husband should see. He may be best served in a larger academic setting with many specialists. A neurologist who specializes in autonomics, as I have mentioned several times, would be recommended. Additionally, your husband may need an extended (24 hour) EEG to observe for any changes to may show epilepsy. Many of times, a 20 minute EEG may miss the epileptic activity.
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.