Responses
I think it's factors combining. Lily's dad did not pick her basket up until for a day or couple of days. And when he did, she was soaked. So god knows how long she was in that situation. Added the fact that she was then raised in space immediately after that.
She's probably sick because she grew up on a different atmosphere. At least that's what I think is most likely. Even i squishy dad adjusted the atmosphere to fit her, I don't think it was a perfect match