My mom's vascular dementia is the result of several strokes. She has particular difficulty with linear time (when things happened or when it is now) and remembering names and nouns.
On top of this I suspect she also had some degree of mental illness (based on my upbringing) and did a lot of gas lighting/rewriting the narrative of how things happened over my lifetime. If you were to ask her, she has always been perfect and has never made a mistake. This makes the dementia harder for her. She can't accept help because that would confirm she wasn't perfect. So it's not that she lost thousands of dollars this year in her house, it's other people are stealing it from her.