I've been dealing with my mother in law's delusions and paranoia for almost six years now. When I first met her, she just seemed like an overly strict parent, until time passed and it became quite obvious that she is suffering from a mental illness. The family has all spoken together and agrees that she needs help, but she is so defiant about having anything wrong with her. In fact, she is under the impression that everyone else in her family has a mental illness or something severely wrong with them.
Many things she has said and done over the years has been absurd, but her most recent delusion has really started to crumble the foundation, or what was left, of their family. Long story short, she somehow came up with the idea that her husband and 20 year old daughter have been slowly poisoning her with antifreeze and various chemicals around the house. She had me come over and perform a black light check on her house to look for antifreeze residue, stalk the history on her husbands computer to find evidence of him cheating or trying to murder her, and forced us to hide a jug of "watered down antifreeze" from her husband in the attic while wearing gloves.... turns out the jug was homemade lemonade. She comes up with random illnesses and constantly checks herself into the hospital only to argue when they find nothing wrong. Every day there something new and insane wrong with her and most of the time she blames it on her husband "poisoning her". She also has a tenancy to verbally attack people, call the police, threaten, and manipulate people to get what she wants.
Its gotten to the point to where nobody can live in the same house as her and she can no longer work or take care of herself. She doesn't even eat any food in the house because she thinks all of it has been poisoned and relies on her son to go bring her food. If anyone even slightly brings up that she needs help or are worried about her mental well being, she shuts down and goes into a tangent. I'm at the end of my rope and don't know what to do. I know that an intervention is needed, but I'm not sure I have enough people willing to attempt it. Have any of you ever experienced something like this or have any input on how I can help? Should I call adult protective services? I obviously can't just take her to a mental hospital against her will, although she greatly needs it. Any advice is very much appreciated. 
