I'm so sorry you are going through this. I wouldn't be giving your MIL any more thought. What you wrote was beautiful and outlined your feelings perfectly. As you don't know where your illness is headed it's so important to now spend time with people that you love. You need the support and love of those around you who actually care about you.

Perhaps down the track you may want to see your MIL for closure but if you see her again it should be because it's something you need or want. At this point your MIL is not important to your life or your happiness. Your MIL is really nothing in your life, so let her go, ignore her, who cares what she rants about, others will see right through her and be horrified by her words and actions. You don't need her around zapping you of your peace and strength. Keep her far far away.