It's entirely possible that he was silentbanned and has been trying to post the entire time but HN is silently rejecting his posts. This happened to my primary account at around the same time edw519 stopped posting. I took a similar position about the Scwhartz situation in my comments on that account. I can log in with that account, but attempting to post comments will either mysteriously time out or no comments will be posted (even with showdead) after a minute or two of pageloading. (This is not a connection issue; posting from this account never has such lag.)
If he was silentbanned, he'll be able to post again the next time management lifts the silentbans.