Someone said my mother qualifies for hospice if she has advanced dementia.The visiting nurses said she does not quality. Anyone know?

Hi Karyll
I am really sorry that your mother has this diagnosis, it can be so difficult. Your question is complex because it depends on the other circumstances for your mother's health as well as what you mean by "qualify".
Do you mean is she qualified under Medicare or Medicaid for Hospice services?
Here is good info on that:
medicare.gov/coverage/hospice-and-respite-care.html
You can get hospice care if you have Medicare Part A (Hospital Insurance) AND meet all of these conditions:

Your hospice doctor and your regular doctor or nurse practitioner (if you have one) certify that you’re terminally ill (you're expected to live 6 months or less).
You accept palliative care (for comfort) instead of care to cure your illness.
You sign a statement choosing hospice care instead of other Medicare-covered treatments for your terminal illness and related conditions.
Only your hospice doctor and your regular doctor or nurse practitioner (if you have one) can certify that you’re terminally ill and have a life expectancy of 6 months or less.

So what that is saying is that her personal physician (or healthcare provider) needs to verify that she is "end stage" for her illness (whether it is dementia, COPD, cancer, renal failure, etc.) and that the Hospice program's physician needs to verify that diagnosis.
If this is something that you want to pursue (and as a former Hospice RN, I would encourage you to look into it, Hospice care can be a wonderful help to the patient and the family), you need to start with a conversation with her doctor. Hopefully, you have a sympathetic doctor that will facilitate her getting hospice care. There is really no risk; if she does live longer than expected, she can be taken off of the Hospice program.
But odds are, if she is elderly, with advanced dementia and any other significant health issues a very good case for Hospice care can be made.
Please do not let one negative Nelly stand in your way. Have a talk with her doctor, if that doctor does not seem knowledgeable about Hospice, you can call a Hospice program in your area and ask for help.
Best of luck to you,
Margaret