My late husband was showing signs some years in advance of his diagnosis with Parkinson's disease ….we had (the docs and specialists) originally thought it may be Asperger OR Narcissisctic Personality Disorder as he was for many years incapable of hearing anyone's thoughts but his own, often with aggressive and bullying behaviour. In the end the Parkinsons diagnosis was eventually reached which although it did not alter his personality traits, did give a valid reason for his behaviour...many times I had thought of leaving as his aggression became violent ...but I stayed and just got on with it. After four years where he deteriorated slowly, he then had to go into care as he could no longer safely remain at home (constant falling, aggression towards the nurses that came in for some medical procedures) ...the only thing he loved was the two cats we had …..so sad. He never accepted he had anything wrong with him which was even more difficult and fought against any help or advice people TRIED to give him......so sad ...but maybe you could have a word with your doctors who might refer him for further tests and maybe a brain scan ? good luck ..hope it works out for you...
Elderly fellow gran has become loudly racist