Suzanna Teller is dying.
This is perhaps an excessively melodramatic way of putting things. The reaper is being polite today; he announces himself well in advance. Zana has as many as ten years of life left, which is plenty of time to get used to the concept. She'll be a shell by the end of it - they won't even know for sure whether she's a vegetable, since motor functions degrade so badly before cognition does, but the same thing that's going to destroy her nerves is going to destroy her brain, and
There are treatments. Experimental ones. They might work or they might not, but it doesn't matter, because Karen is working three part-time jobs already just to pay the bills, and insurance will never cover it, not for this. It's too expensive and there's too little hope. It's going to take her months just to pay off the cost of determining what was wrong.
She explains the situation to Connor (who is eleven now - Zana might or might not make it that long), and then excuses herself from Zana's hospital room and stands in the hallway and cries.