Do not reason, argue, or challenge the delusion. Attempting to disprove the delusion is not helpful and will create mistrust. Assure the person that they are safe and no harm will come.
How do you deal with delusions?
Avoid arguing with the person about their delusions. Delusions are extremely fixed and difficult to change. Connect with the emotion of the delusion or hallucination e.g. It must be frightening to believe that all your water is poisoned. Calm things down—reduce noise and have fewer people around the person.
How do you communicate with someone who is delusional?
When speaking to someone who has delusional disorder, be conscious of tone and word choice. Try to come across as non-confrontational and calm, expressing concern as a form of opinion, rather than judgement. It is best to talk to your loved one about your concern when they are not in the midst of their delusion.