How can my mom deal with her younger sister who is nasty?

My aunt is a liar and plain nasty. About 7 or 8 years ago when I confided in my aunt with the problems I had with my sister she swore that she will not tell anyone. But every time I talked to her about my problems she told her 3 daughters and they told my sister that I was talking to their mom about my sister. When I was planning my wedding to my husband she would call me at work and stress me out. She told me that I was the one who was not telling the truth and so was my sister. She said her children would never tell any lies. My aunt was angry when I got engaged to my husband and didn't tell her right away that I was engaged. After I got married and had my son my aunt, her husband and her children started ignoring me. I went to a family gathering 2 years ago and she totally ignored me and didn't even come see my son. Now she is causing problems for my mother. My aunt sponsored us to come to the U.S. 23 years ago. She holds that against us. When we moved to the U.S. 23 years ago we moved in to their house. My aunt and uncle took a lot of things that belonged to my mother. One was my mothers old photo of my grandmother and my grandmothers sister. My aunt has taken my mothers gold Jewelery which my grandmother gave to my mother. My aunt said that my grandmother promised to give that Jewelery to her instead of my mother. When my mother sold our old house back home in our country my aunt wanted half of the lands money. My mother gave small portion of the land from our house to my aunt. But when my mom sold the land my aunt wanted half of the land. My mom had a piece of gold jewelery made for one of my cousins when we move to the U.S. She made the identical piece of jewelery made for me too. My aunt saw my jewelery and asked that from my mother. She said that it was her jewelery which my mother was going to give her but she never got it from my mother. My grandmother gave my mother and my aunt 2 separate lands years ago. The land cannot be used because my country of origin is at civil war. My aunt told my mother that my mothers portion of the land belongs to her too because my grandmother promised to give her. My grandmother has been dead for 30 years now. Recently my uncle had told my mother that my mothers antique steamer which my mother got from my grandmother belongs to him. He said that he took a picture of that steamer and my grandmother years ago. Back home we never owned a camera. We never got a chance to take any pictures. He said when he asked my mother about this steamer years ago my mother laughed it off and didn't give him an answer. He and my aunt badgered my mother so much that she gave in and said that they could have that antique steamer. When my grandfather moved to the u.s. in the mid 80's my aunt and her kids tormented him. My aunt would listen to her kids lies about my grandfather and took her kids side. My grandfather is dead now. When he moved to he nursing home they took all stuff and his books. Her kids does not know our native language. He had bibles and prayer books from my language. Now after my aunt and uncle pass away I don't know what is going to happen to his books. When my mom went through Id theft she lost over 10 thousand dollars. My aunt went to the bank with my mom and she saw how much money my mom had in her account. Instead of feeling sorry for my mom the first comment from her was "you have a lot of money". I am afraid that she is going to take all my mothers things one by one including my mothers jewelery one of which my mother is going to pass on to me which belongs to my grandmother. This specific chain and pendant I wore at my wedding which my mom said she is going to give to me later on. (It is my grandmothers). I would like my sister and I to get some of my mothers things to pass on to our children. Her kids don't have any children. My mother does not know how to drive so every time my aunt invites her to spend the weekends at their house they pick her up. They always talk politics and religion and my mom says that she doesn't want to listen to politics and religion all the time. When my mom is in need to go the doctors they never help her out. My mother is scared of my sister. My aunt is loud and she believes she is always right and her kids never lie. My mom thinks I should make amends with my aunt. How can I do that? what should my mother do? For all the holidays my mom goes to her sisters hows because she is scared that my aunt is going to get mad. What should my mother do? Should I not worry about it and move on with my life? Please I need an answer. Thanks.