I'm absolutely not offended, it's just the first time I hear about this and I can't find any supporting information about it. Even in the last link you provided, americanoverseas.org, I still can't find any mention of owing taxes to the US, 10 years after relinquishing your green card.

The only thing that pops up time and time again is the expatriation tax which only applies if you had your GC for 8 years.

I'm really sorry about your neurological diseases, it's such a shame US healthcare is in shambles for the general populace.