Alice,
This truly seems to me to be an issue of boundaries. If ABF's mom were a perfect stranger and walked in your home spouting hurtful, hateful things at you, how long would you allow her to stay?
So I find myself stopping short when I remind myself that other people hold opinions of me that are none of my business because I can't seem to justify that being true.
Her opinions of you ARE truly none of your business. It is a sad but true fact that not all people are going to like us -- I consider myself a pretty cool person and I can still name quite a few people who don't like me, my style, my smart mouth, my dogs, etc. But my acceptance of this fact is a recent development...when I was younger, I still took it very personally and couldn't fathom why anyone would dislike little ol' me!!
So, since you can't control her feelings about you - you do realize that, right? That she's going to feel what she feels, no matter what you say or do? -- all you can do is set boundaries as to how much you will tolerate when you're around.
Honestly - she will continue to spout hurtful things for as long as you'll sit there and listen, or as long as you continue to make her welcome in your home without any repercussions for her rude, insensitive behavior.
It takes courage to get in someone's face and say, "The next time you say hurtful things about me in my presence, I am going to go to your room and pack your bag, and you will not be welcome in this house again. If you do it to me at YOUR house, I will leave. Is that pretty clear?"
It takes courage, and I had to be pretty mad before I could do it (and yes, I have, and yes, it worked) It's the only thing that will make her change her behavior. YOU have nothing to feel bad about...she's the one who's behaving badly and she has lost her "guest rights" imho.
GL
p.s. meds or not - she will remember being tossed into a cab and sent home for bad behavior. And at the very least, she's out of your airspace and you can be at peace. Nobody needs that in their face.