No, I don't pity them. They are perfectly able to function in their own way. A lawyer my family hired (Husband of my mothers friend) was involved in a car crash when he was in his late twenties. Had a lobotomy and had roughly half of his brain removed. he studied and got his license back again and was in the courtroom defending people again.
Though I am speaking of physical disabilities. Those who are mentally handicapped , I do pity since they mind can think around a physical disability (deaf,blindness,loss of a limb) but, if you brain is damaged or severely impaired you are basically S.O.L.