Good point, but she was very ill long before this latest impeachment push gained much steam . . . but Trump has pummeled the liberal bastion of the 9th Circuit here in recent days. It certainly is at least a big part of their motivation.
Possibly her health was somewhat stable after the lung cancer diagnosis. However, her condition could have worsened or she has given signals that she will have to step down. Whatever the case, you can bet that this is a driving force behind the DEMS big push.