People with NPD do NOT have testamentary capacity. I am not a lawyer or a psychologist. I am a linguist; I pay attention to language. My late father was a malignant covert narcissist; of that I am certain because in my 55 years of life, I have had plenty of chance to observe him (more than a psychologist who might see him for only 55 HOURS in an office). Testamentary capacity was originally described (what it is and what it isn't) in the 1870 decision Banks v. Goodfellow by Chief Justice Cockburn. Modern psychology's understanding and description of NPD has been refined much over the last couple of decades. I hope people who have had to deal with a narcissistic parent or spouse can look at what I have posted and agree with me that both the law and psychology need to come together to discuss this further to help end the suffering we endure even after our "loved" ones are dead and gone.
Some interesting parallels appear when NPD and the 1870 decision Banks v. Goodfellow are compared side by side. The following is a transcript of some videos I recently posted on YouTube. (My voice isn’t what it used to be, so I decided to post here also.) I’m hoping people will read this and find what I’ve put together worthy of consideration.