How wise you are to seek further evaluation of your wife’s cognitive issues. I had not heard of fibro fog but did a little research and indeed it can causes dementia type behavior. Also your wife is at the age of menopause which can also cause hormonal imbalances that affect cognitive ability. I hope your wife would agree to a thorough physical and neuro psyche work up beginning w your PCP.
Sometimes a doctor needs to know you are ok to pursue this more so that you both know what you are dealing with and how to proceed. I wish you so well with hope and prayer.