Assalamu alaikum - My mother might be passing away

Assalamu alaikum. Inna lillahi wa inna ilayhi raji'un. I don't even know how to say this without breaking down. After everything my father did to her they're still married and my mother stayed for the children's sake. My faith feels shaky sometimes when I think about all she endured. She is such an honest, simple woman. I spent time with family this long weekend and before I left she told me the money I was saving for her should be used to buy her a burial plot. She asked me to get one soon because she doesn't want to be buried next to my father, even though he bought two plots years ago. She said his money came from haram sources and it has poisoned our home. My mom doesn't care for worldly things. She's a Quran teacher and she used her halal earnings so she could have a grave bought properly and be away from him. Just thinking about that has me crying - the only thing she ever saved for in this life was a place to rest. How can Allah let this happen to my mother in this life? I feel so lost. I will honor her wishes because she seems to know how long she has. I didn't expect to possibly lose her so soon. Our relationship was complicated. I dedicated my completed PhD to her and even named a theoretical framework after her - I wanted my research to be a form of sadaqa jariyah for both of us. How else can I honor her while trying to understand how women are treated? May Allah have mercy on her and give me patience.