As a newbie I had only just picked up on the magnitude of the loss of Sensei's constant presence in e2 when I was suddenly elated to see his name appear briefly a few days ago in the Other users nodelet with a sweet /msg about having 600 /msgs to get through in the Chatterbox.
I have an image of him diligently plugging away at all those /msgs, cup of tea at hand, feeling better and soon to return.
May it be so.
Addendum
Sadly, I later learned (as stated on his homenode) that "recent "last seen" dates are just Jinmyo checking sensei's msgs for him."