some suggestions

It happned to my wife. This is a mental illness called delusion. She refused to see doctor and take any medicine at the beggining as she thought she was normal and what she deluded was true. So I sent her to ER. Then she was admitted to the hospital. the 1st medication was Haldal as I remember, but it had huge side effects. Then the Dr changed to a brand named medication. I forgot the name.

this illness needs medication. If the medication does not cure after one year, the Dr needs to change the medication.

This is a tough illness. As the spouse, we'd rather prefer a physical illness as mental illness is frustrating.