Just a guess here, but he's probably a student? The falling off the grid so to speak seems to correlate with school starting. Believe it or not most of the people on here probably have real jobs and/or school of which have nothing to do with their bitcoin projects on here. Fall time (at least fall time here in the US) is a pretty busy time of the year for most people. Getting blasted with PMs and Emails I am sure there are a lot that get ignored and/or forgotten about.
Retired.
And I suspect like everyone else crest fallen given the monumental cock up that is Avalon chips not shipping. As suggested we all need to give BKK time to regain his feet, and get that floor done then when he is good and ready he will resurface. I to hope he is well and no matter what I want to thank him for all the work he has put in a better effort could not be asked for to be honest. Let the man recoup his sanity and come back at his own pace and terms.