Mental health aggression dementia behavi

My father had a heart attack 3 years back and since then he is having mental health issue primarily anger issues, always complaining of itching,keep on scratching even though no signs of itching, he would not listen to anyone keep on repeating same thing, signs of dementia, would not follow cleanliness when he go to get fresh and would not understand if we try to tell often leave his bottom soiled after he go to toilet and would not try to understand when we explain. We were consulting psychiatrist but that hasn't been working well apart for small duration.few days he started feeling very unwell and stopped listening or responding to anything even had trouble saying anything started talking to his reflection in window so we put the medicine on hold We are not able to figure which doctor should we consult.