Are memory and cognitive changes expected after a stroke regardless of the area affected?
Although the cerebellum and brainstem are not commonly associated with cognitive and personality changes, there is no question that these things can occur with strokes in those locations.
With regards to the cause of the stroke, I agree with you that it is always best to try and identify exactly what happened. I would call the nearest academic University Hospital and ask for an appointment with one of their Stroke Specialists. If they have none, branch out to a regional University - such as the major university in your state. It is important for treatment to get a better understanding of the cause.
As for his symptoms, they should recover slowly with time (I cannot guarantee full recovery) if he actively exercises the skills that are lacking. Reading, crossword puzzles, taking an elective class at a local college, etc. are very helpful for this.
As a final thought, if you want to better quantify exactly what deficits exist, I would seek out a local Neuropsychologist. These are typically PhD doctors who spend several hours testing different elements of cognition, and are often very helpful in aiding the medical doctors with a tailored treatment plan.
Good luck!
