How Do You Deal With A “toxic” Parent?

How do you deal with a parent who was abusive and is toxic to you as an adult, is narcissistic, angry and emotionally unstable? I have already limited contact with this person. Whenever she talks she does this fake “sad” voice and says things like “I wish you would forgive me and trust me, your behavior is killing me.” Etc, etc. For people who have dealt with toxic and manipulative parents, how do you respond to this behavior? How do you have a relationship with someone who is very self-absorbed and manipulative, but loves you as much as they are able? I know this person loves me as much as she is able, and I don’t want to cut her out of my life if possible (I haven’t seen her face to face in years, speak to her on the phone maybe twice a year), but if there are any ways I can dissuade her from using the same manipulative tactics, that would be great. it goes something like this:
Mother acts out and resorts to verbal abuse because she feels unloved and unwanted (I don’t trust her, that is true, but that is not going to change over night). She hams up the melodrama and despair in order to make me feel sorry for her (including her never ending series of medical problems- last time I spoke to her in person she said she had “end stage kidney disease” because she “missed me so much” and she DID seem physically ill, so I was legitimately upset but she refuses to see a “western” doctor because they are “useless”- so basically she will proclaim she has diseases without having a diagnosis). This irritates me and I end up snapping at her and acting aloof or more uncaring than I actually feel because I don’t like crocodile tears or having my buttons pushed. My “uncaring” response makes mother feel even more unloved and she tries even harder to seem pathetic and miserable next time. Is there any way *I* can put a stop to this cycle? Because she doesn’t trust western doctors, I have tried sending her advice relating to eastern medicine and homeopathy and her response is to get arrogant and say something like “You are lecturing me about my health? I was interested in alternative medicine before you were born, so don’t preach to me…” I am a terrible actor so I can’t just act upset or sympathetic to placate her when I don’t feel it and no matter what I say or do, she finds some way to put it down. If I show interest in her, it’s not enough, or I am not paying attention to her beliefs by suggesting she see a doctor, and if I try to show an interest in alternative medicine (one of her main interests) I am being arrogant and condescending because she knows so much more than me. I tell her and show her in small ways I love her, but she seems to want a huge show of emotion. I have asked her to be my pen pal so we can stay in touch in a relatively “safe” (for me) way and she outright refused, saying she doesn’t have the time (she doesn’t work regularly)- she never wants to talk to me on the phone (she is paranoid, I think, that she is being recorded, and because she knows she abused me she is paranoid I will tape her- she even phoned me on christmas morning once to beg me not to sue her). No amount of affection is ever enough and over the last ten years she has lost all the friends she had while I was growing up and managed to alienate her siblings.
Advice from people in the psych community would be welcome, I am out of ideas.I have suggested she see a therapist and you can imagine the response, but I KNOW she is a miserable person and if there is any way I can help her to heal or at least get well enough to get some pleasure out of life, that would be great.
Please no mean spirited responses.