What if someone refuses to go to a nursing home?

Call Adult Protective Services and report her as a medically vulnerable senior with no help

People retain the right to make their own choices - even if those choices are bad. Two possibilities. She could assign guardianship to someone willingly with a power of attorney. Otherwise only a judge can transfer guardianship of her to another person.

Without guardianship, no one can legally force her to do anything at all. Elder abuse laws protect seniors from abuse but also prevent loved ones from doing things the senior doesn’t want but are obviously in the senior’s best interest.

I had to lie to my dad to make him move out of my apartment and into a care facility. It was for his own good so I don’t feel at all bad about it.

Call APS for wellness check. They can give you some guidance. Let them know you are walking away from helping at home. Truth is that Beatty here is right in that "there will be no solutions if you are all the solutions". Let APS know that you suspect she is unsafe and need guidance about how to get her assessed. If they agree an ambulance should be called they will get you referred to social services who can get you appointed as temporary guardian if need be. HOWEVER, do know that if she fights guardianship in court she may win. The state is loathe to take a citizen's rights from her.
There really is no good answer here. If the state is made guardian they will place her, but at that point you will have no say about where she is placed or what fiduciary manages her assets or how they are managed.
Are you alone in being responsible or are there other siblings nearby.
Wishing you luck, hoping you will update. Sometimes there are no answers until an elder does eventually and INEVITABLY come to grief from being alone and having an accident. We have even seen cases on Forum where a child tried with all her might to get help and her mom died in the home without help. It is very sad and tough. Again, I am so sorry.