My mother is 80. She is refusing respite care. I think she will also refuse ALF in the future. What can I do to convince her to accept help?

She’ll accept help when you stop helping. That sounds harsh, but she has no reason to accept help while you’re being the help. You’ll never convince her of anything, that’s a wasted effort. Don’t be available and don’t feel you owe explanation for your decisions

If you are her caregiver, stop doing for her. Your profile says that you yourself have multiple health issues, so just tell her that you can no longer help her, as you now have to help yourself.
Perhaps without your help or anyone else, she will come to realize that she needs more help than she realizes, and be more agreeable to making the necessary changes. Good luck.