I go to her apartment to help her (she's a hoarder), when I try to keep all in order, she yells at me to get out, and hits me. If she starts hoarding again, she will get evicted. No help from other 2 siblings; they don't want to deal with her drama. Please give advice.
Where will she go if she is evicted? Sounds like a real possibility. Do you want to take her into your home knowing the risks? She will hoard and become combative in your home too.
You need help. Go to her doctor and anyone else associated with her and ask. Call APS, your local Area Agency on Aging or Health and Human Services. Every state has programs for the elderly. If you call them and keep after them, you’ll find help.
I don't think anyone should tolerate physical violence. It crosses lines and proves her executive function is not there.
Before she hurts you or someone else she needs intervention.