How do you deal with your loved one not dying a peaceful death because of anger?

My mom and I had a very unhealthy relationship my entire life. I am the second youngest, and the only one of my siblings to leave my hometown area and move away. I was the first to go to college. My mom did not want me to go to college, she made that very clear. She has resented me for 30 years for going anyway and told everyone that. I moved away as soon as I graduated. I tried to maintain a relationship with her, but it was very hard. The only times she ever called me were when she needed something. My dad died when I was a toddler. I have three living siblings: older sister is on the spectrum, works a minimum wage job and lived for the past 25 years in a mobile home practically in my mom's back yard; oldest brother is an alcoholic (recently diagnosed with alcohol related dementia). My younger sister is an addict. She is also an RN but has been fired from more jobs than I can count (stealing meds, no-showing). My other brother passed away of alcohol related issues. My mom was diagnosed with stage 4 cancer a year ago. Before we got the diagnosis, when she first started having symptoms, I went down to be with her for the hysterectomy and subsequent recovery. Even though my other siblings live close by and I'm 240 miles away, no one wanted to do it because she is so difficult. What we expected to be an outpatient surgery ended up being a 22-day hospital stay with several very close calls. I stayed with her from the time she went for the surgery until she was released and was able to go home. I helped her go to the bathroom, I emptied her drains, I emptied her catheter, I bathed her - all things that are very personal and I knew she would be uncomfortable so I tried everything I could to make it less so. I reminded her how many times she had changed my diapers, fed me, etc. Mom resented me and made it clear she wished she had someone else - anyone else - to take care of her. My older sister did not want to help. My younger sister came twice to the hospital but was so high both times the nursing staff asked me to ask her to leave. My brother was in no shape to help. Every other person in her life she has alienated with her hateful attitude and constant character attacks. She alienated my aunts and uncles as well. I put my business and my life on hold while she was sick because I wanted to her get good care and she wanted to be at home. After a few months, the cancer took away her ability to get out of bed. Still kept her at home, changed diapers, carried her to potty chair, tried everything to keep her at home but mom got very combative and one day a visiting hospice nurse saw her hit me and implored me to put her in inpatient hospice because she refused to take her pain meds and I was at my wits end. Mom hated the hospice although it was lovely. She called the nurses and chaplains names. She bit a syringe in half the first night she was there and then smugly said "you are lucky - I was going for your finger." The chaplains tried SO very hard to get through to her. They asked her if she had anyone, she needed to make amends with because she lingered on and suffered for weeks. She told them a lot of people had wronged HER so they should try going out and finding those people and bringing them in to apologize to her. She refused meds (pain meds, which was awful, and I begged them to give them to her anyway because otherwise she was in excruciating pain). One of my aunts came to visit and mom told her I had put her there "in this bad place" and no one could find her. The reality was no one wanted to visit which broke my heart for her. She called out for my dad and for her mother and would angrily scream their names because I guess they did not answer. She kept seeing a man in a black hat and overcoat behind the door. I hear about other people seeing people in white or family members. I am haunted by the fact she died so angry and with so much hate. And I cannot find peace now because of it.