My mom was diagnosed with MCI and her husband is not giving her the proper care.

Her daughter has taken complete control of her. I don't believe she is capable of making a decision whether to go to the doctor. I don't believe that I can independently take her to the doctor. I was hoping for a solution involving elder protection.

Molly, does your friend want to see a doctor? What if she schedules an appointment and you take her? Or are the friends symptoms beyond her making an appointment for herself?

A close friend is showing clear signs of dementia, possibly Alzheimer's. Her daughter continues to deny the symptoms and will not seek medical attention. She schedules and then cancels appointments with her doctor. I believe there to be a financial reason since the daughter relies on financial support of the mother. Any thoughts of steps to get medical attention for my close friend?

When did this abuse start? If it is long-standing and she has taken no steps to correct the situation I would say there is little you can do.

If her diagnosis is MCI I doubt very much she would be found incompetent and in need of a guardian.

Is the abuse long standing? Does your mother want to leave her husband? It might matter as to the course you choose to take. If she wants you to take care of her she could possibly sign a DPOA for health and finance and you could start making the decisions. But if she is afraid or unable to make changes you might have to file for guardianship. You need to understand your state laws. A conference with a qualified elder attorney could guide your actions so you make the right decisions. Hopefully others who have experience with this will see your question. I know this is heartbreaking to see your mom being abused.
Do take immediate action. Her situation is not likely to get better without your help.