Sleep walking and talking is not that uncommon in children. Changes in visual depth perception is uncommon. I'd start with an Ophthalmologist. That is the easiest and least expensive. Then a Neurologist. The Neuro would be the best to decide if there is a need for an EEG, Sleep EEG, MRI, etc. The Neuro would be the best to interpret the EEG or sleep study anyhow. You could also see if there is a Neuro-Ophthalmologist.in your area and get both evaluated in one visit.
Bob
I would have a sleep study done on him. You might also want them to do an EEG to rule out any kind of seizure activity.