Developmentally disabled, non-verbal; seizure disorder and 41yrs. old; not sleeping; ct scan show dilated ventricles; is this hydrocephalus?

Yes & no: If there are no physical signs of increased brain pressure (found on exam), this is likely a form of hydrocephalus called "hydrocephalus ex vacuo". In short, the ventricles can be bigger if there is not the normal amount of brain matter to fill the space. It is a stable process that would require no treatment. It can be confirmed bt the doc.