My father is undergoing testing for dementia and under the care of a neurologist. He is clearly having more difficulty with daily tasks, communication, etc. My mother is his only daily contact in life. She has always been a negative person, prone to biting, bitter comments. I am concerned about the way she deals with him now, so short tempered and nasty. He has reached out to me several times over the past year and indicates it really hurts him. I am an only child so I am the only referee. Should I step in here? She indicates he says mean things when I am not around, but I believe that's mostly the dementia, as this was not formerly his nature. I think she lacks the tolerance and compassion to deal with this...I am concerned for my dad's emotional well being.