Thank you for your replies. This is a very scary and stressful situation. I completely agree that spur-of-the-moment absences are disruptive; do you know any accommodations for this sort of thing? It's very similar to an epileptic person who's medicated, but will always be at risk of a seizure.

So it the plan now is:
- Get/file updated FMLA and ADA forms
- File EEOC and WHD complaints if they continue to try to deny use of FMLA/refuse to help with accommodations for sudden onset symptoms
- Continue to look for work elsewhere

Is that about right? I have a lawyer who's willing to write my company a letter stating that they're going about this the wrong way, but with no income, I can't hire them. Should I accept their terms and go back to work, or would that mean that I'm willingly waiving my rights?

I'm not sure if it helps but since I work remotely, I have all of this either in writing or recorded. (One-party consent states.)