How to handle a narcissistic mother?

My mother is narcissistic. We use to get a long very well when as younger but now as I’m getting older and realizing who she really is- I can’t stand her. For example my grandmother fell and I kept urging her to take her to the hospital but she kept brushing it off saying that it was nothing. I kept saying that she definitely broke a bone and she kept arguing that she knows better and that she is going to be fine. A few weeks later she died. It has left the biggest hole in my heart and I keep wondering ‘what if’ and that she would still be alive if my mom let her go to the hospital in time. For everything in life she always blames other people never her self. For example for my gmas funeral she forgot to get a priest (nobody showed up). We were all so mad and she said it was the funerals home responsibility. I even invited my bfs parents and they were so shocked. I felt so embarrassed and ashamed. She is the most irresponsible person and blames others for making mistakes. How do I distance myself from her even if I am financially dependent on her without driving myself insane?