I've deliberately avoided this confrontation for the last 22 years. That's because when we had it the first time, my mother didn't speak to me for two years. She became convinced that I was "demonized" and was trying to lead her away from the Truth.
It's a decision we all have to make for ourselves. I decided that I'd rather have a part of her in my life, as long as I could set some boundaries, than to simply cut the relationship off. Not everyone can make that decision, and sometimes I'm still not certain if it's the healthiest one for me. But it's what I did. One of my therapists told me that, for a child, it's better to bond with an emotionally abusive parent than to not bond at all. I guess that means the lesser of two evils is, waddaya know, less evil.
However, I've worked very hard to set boundaries in the intervening decades. For example, when one of those strange blind spots she has about reality comes up, I just say, "Well, Mom, you know we don't see this the same way at all, and if we keep discussing it, we'll end up with hurt feelings. Let's talk about something else." Sometimes she ignores that and plows ahead, but then the consequence is that the conversation is over and I stay away for awhile. She's slowly--as in, slower than Pavlov's dogs--learning not to press me. And I try to return the favor.
This won't work for everyone. As I noted above, I'm not even sure it works for me. But it's the best I can do right now, and if it seems like it might be a helpful approach to you, feel free to give it a try.
Jankyn