How can I get my mother to use her walker? And how to know when is the right time for memory care?

My mom has been living with me since she was diagnosed with Lewy Body Dementia 3 1/2 years ago. Her doctor recommended a walker last year because she has Parkinson symptoms that cause her gait to be off balance. Mom refuses to use the walker and over the last week she has fallen twice. I try my best to keep an eye on her at all times but this just started happening in the middle of the night. I have ordered a bed alarm and I have sensors through out the house to wake me if she leaves her room. She says walkers are for old sick people and she kicks it away when I bring it to her and now she is displaying anger toward me. How can I get her to use her walker and how do I know when it's time for her to be placed in a memory care facility.