The rental house has a tub. I would prefer a walk-in shower but can't get one. She has me and my sister to help her when she needs it. I think that she needs a aide to help out with her care. My sister and I are both worn out. Mom is refusing to let me get some help.
I LOVE those no-rinse products and sometimes use them myself.
Get aides in to help. Explain they are there to help YOU & your sister.
That is exactly what my Doctor told me in a similar situation.
As careful as we are, non slip mats and safety bars, the risks are still there for falling.
Allow her to wash up with a pail of water and soap or the no rinse soap if you need to. My mom took a shower once a week but sometimes when she was too tired she did the sponge bath.