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.