She's been in and out a lot.
Again, not wishing ill will, but I think she might be retiring, or forced out by health before the next election. Which could be good or bad politically, because it would absolutely energize the dem base to vote for "anybody but Trump". From that perspective, if she doesn't retire before the year is out, it would almost be better that she stay in until after the election.
Non-politically, as I have said before, I wouldn't want to see anyone, whether I agree with them or not, risk their health because of a political ideology. If she's really sick and suffering, she should retire, regardless of political consequences to either side, to have some peace in her remaining years.