My mother-in-law has not been diagnosed but is getting worse: leaves cook stove turned on, loses her meds, gets very contrary, accuses husband of cheating (85y/o), has open water bottles all over the house, always talking about dying, can't hear well, thinks she's being talked about. I think she would be too contrary to submit to any kind of psych test. Thanks
Is her regular doctor someone who just looks at blood tests and says " she's fine"? If so, you need to find a geriatrics doctor who will listen to your wife about her mom's behavioral changes.
With the family in agreement, I'd get mother-in-law to doctor, letting the doctor know what she has been experiencing. Based on the diagnosis, the family can explore what options are available for her care, if it's dementia.