I understand your concerns. From your history i understand that your brother had an head injury
5 years back and had a seizure episode and was put on these medications. When you say nothing has changed much, do you mean to say that the seizures are still persisting? Another vital information that is missing is what did the brain imaging show at that time or for that reason was he ever scanned by MRI/CT. From the complains that you have mentioned like shakes alot, unable to speak or eat properly and obvious change in his personality, it appears that your brother had some obvious brain damage
. These symptoms are generally not explainable by seizure disorder
alone. It will be better to get a fresh MRI and consult with a neurosurgeon or neurophysician .
Thanks. Hope I am able to solve your concerns.