Recently, based on observations and a little research, I thought a family member had the traits of someone Gaslighting someone. It was the narcissistic traits and the relentless nature of her behaviour (two, three years) that caused, and still do cause, that underlying feeling of uneasiness about her motives and her desires for the future.
Now a diagnoses of Boarder Line Personality Disorder has been given it now becomes a reality that can formally be addressed. This will, like all the other mental health things going on in our family, take time. Whether any relationships can be salvaged is unlikely.