Does MIL have a history of Mental illness? Or could this possibly be dementia related paranoia/delusion/psychosis?

You should consult a psychiatrist, he/she will be able to point you towards the right steps to take.

My mother is 50 and has had paranoia schizophrenia for many years now. We haven't been able to get help for her because she is in extreme denial, smart and has managed to function in society. We have tried almost everything...

You need to make sure you take care of yourself and your wife first. I have gone through hell and back but was very lucky to have my husband stand by me. At times he was the only person who kept me going and kept me sane.

You also need to know that this kind of disease progresses and your MIL's paranoia may progress towards the rest of the family.
Also in my experience the more I try to reason with my mother the worst it is. They don't think like normal people and no matter how you try to explain it to her, her delusions are real to her, no matter what you say so it's better to avoid confrontation.

Please seek professional help and come up with a strategy that the whole family will follow.

Best of luck and God bless,

Denisse

How would you get help for someone with delusions if they don't think they have them? My mother has delusions of reference, and paranoid delusions. I have been trying to get her to tell her primary care doctor, or a psychiatrist, for years. She says that only certain people in the community know that she is "out there" and that if she told someone who didn't know her, they would think she is crazy. So she realizes that it "sounds crazy" to think that everyone is out to get her, and yet she is convinced there is a conspiracy against her.

I called her doctor, and they said that they will 'take a note' about my suspicions, but unless she brings it up, there's nothing they can do. And she will NEVER bring it up. I've thought about having her taken by force to a psychiatric hospital, but she will never forgive me for that, especially since she is already very concerned about the idea that people think she is crazy.