How do I report verbal abuse to my mom from my sister who also financially abuses her?

My mom has expressed that she will love to live with me, that no one in my house will make her feel bad about herself or make her use a wheelchair all day when she is able to walk( walker) nor yeld at her or tell her what to talk about or not to her kids, she is always on speaker when we call. She is also told who can came and visit to her apartment ( mom pays the rent) she feels that my sister will not have a house if she decide to move out, she doe not want to give my sister any legal problems but she cries a lot when we talk about leaving my sister behind and move to my house. All my sisters and brothers know my mom is not happy living with my sister but my sister had worked her mind so much that my mothers thinks she stink because she is old, she will be in our way to do things, she is to hard to take care off or is a big hassle to carry all her stuff ( wheelchair, diapers, walker, etc). She also now get very nervous when my sister is around, she will star folding a paper napkin in 20 pieces and unfold and then cut it in 2000 pieces but is only when she is around. She had visit me for up to 3 months and she acts deferent, she is always calm, eats what she likes, my sisters can call at any time she has her own phone in her room, nobody tells her what to do or not what to say or not, she actually talks with us or on the for longer times of periods like 1 hour or so. Last visit she told me my sister does not help her to bath any more she just opens the water for her she has to clean the toilet after she poops ( she even showed me how). My sister leaves her along for long periods of time, she is bing told not to open the door when my sister is not home, my sister is afraid that a social worker can show up at any time and they will stop her pay check ( she gets pay a couple of hours per day for taking care of my mom). I want to bring my mom to live with me so she can enjoy life she is 83 and do, eat, talk what she likes and wants, I strongly believe she will be in better hands and condition.