How do I tell my mother she can't live at home anymore?

I don't if this will help but, here goes. I have a single aunt who lived alone for many years, a retired teacher. When her behaviors began to become irratic and she started to act strange in church and other places, a fellow member of her church referred her to a counseling agency who allerted me to the fact that they took her to a doctor who determined that she had dementia and would be best in a nursing home. When asked to become her guardian I refused and a neutral third party was contracted to communicate with her, have her admitted to a nursing home, and work to handle her home and personal affairs. This worked well and she transitioned smoothly. Had I been involved she would been uncooperative with everything. Perhaps by getting a neutral third party such as a doctor involved in her case, a social worker, her cardilogist or someone like that talk to her about the necessity - and benefits to her - of entering as nursing home, she will think it over and concent to a nursing facility. Many have great activities available for those who are able to participate. Good luck.