chronic schizophrenia patient treatment

My sister (age 40) is schizophrenia patient for past 20 years. My parents moved to Bangalore from chennai 5 years before for my sister treatment, she has been getting treatment in Abhaya hospital, Nimans Hospital(most of the time) and also Manipal Hospital in Mangalore. She used to be normal only for few months after the treatment. Recently i lost my father to covid and this had very bad effect on her and rest of us. My father was taking care of her 24/7. Now she has become more violent and out of control after he passed away. Dr in Nimans hospital told she also have behaviour issue which has to corrected by sending her to rehabilitation center but first she need psychiatric treatment. 

I'm the only breadwinner in my family and i work in Dubai. I had to leave my mom in this diffuicult situation but i had not choice.

My elder sister arranged caretaker and got her admitted to Nimans hospital but it didn't work. She is fat and getting her vein was very difficult, she refuse eating food and very unhygienic . Even the nurse gave up and caretaker also was not good. We brought her back to home.

My mom is too old to take care of her and she is alone. My elder sister is married and she sometime come for her rescue and i'm in Dubai now. I'm helpless and i don't know what to do. I'm also looking for caretake to stay with my mom. Please suggest me what can i do to treat my sister and my bring my mom from this ordeal.

Some of the behaviour issue of my sister is,

1. Doubt everyone and call us Devil and get violent.
2. Refuse to take food.
3. Refuse to take bath, she is very unhygienic
4. Refuse to take medicine 
5. No physical activity