What do you know about Medicare coverage?

My mother is nearing 80 and is progressing into dementia. If she continues like her mother did, she'll soon need someone living with her all the time or need to be in a nursing home to make sure she's taking care of herself, eating well and not wandering off. And then she'll live well into her 90s! She has virtually no ets - just a car and household items, a low life insurance policy (probably enough to cover funeral expenses only). I have the opporutnity to get a good deal on Long Term Care Insurance for her, but I don't know if she really needs it. Will Medicare pay for her care - whether at home or in a nursing home - since she has no ets? I don't know if Medicare is the same throughout all states or not...if it makes any difference, we live in Minnesota.