1-I would like to know the situation of zenith at the last volumes of there series is there anything new about here state? will she get better by anymean?
2-Will we get a better understanding of her situation?
Her state can't be changed. We learn some things that she gained with her new state. (if you want to spoil yourself, just ask)
I can't recall if it is explained how this happened, just got teleported there and ended in that state. (don't remember the cause of her state, maybe high mana exposure? please someone correct me)
We will understand her situation more, but we don't exactly know yet about the cause of it. And, no, by the end of the series, there will be nothing new about her state. There's a girl who also has a similar experience, according to Elinalise, and possibly if we ever get an MT sequel, we will understand more about this "disease".
Elinalise was that girl... it's why she has that curse, and someone thought that using Elinalise as an example might cure Zenith. I'll not say anymore then that unless you want spoilers.