I am a professional psychotherapist and have worked with children and families for 20-some years. However, I have worked with severely mentally ill adults for the past 5 years.
One gentleman I have been working with is very delusional.
He's a really nice guy, he has a tremor in one hand from years of medications, often I believe he wasn't monitored properly.
He insists that his name is "Mick Jagger" but responds politely to his real name. I have watched him socialize with new people and introduce himself as "Mick".
I was talking with him recently and noticed he was looking a tad cleaner, like somebody at the care home in which he resides is taking better care of his clothing. He was nicely and cleanly shaved a couple weeks ago. He smiles a lot.
I have a good rapport with him, partly because I insist on being 'genuine' with people and partly because he's just a good guy: I asked him recently "How old are you?"
"I'm 83" he replied. I looked at him and said "You are not 83".
He replied "I was born 70 years ago at the age of 13".
I question him about actually being Mick Jagger and note he was born in Alabama. He says he was born in Alabama AND England.
When people are seriously delusional there is no discussing their delusions with them.
Negotiation is out of the question.