Hasan tweeted last year he was moving to Japan if Trump won (Trump won). He then went onto a podcast located in Japan that (outside of the America tour) only has guests if they're in Japan, and appeared for a second time, where he said he was back in Japan permanently.
He was probably joking, but he has the means to do it for real. It looked like pictures of his ISIS fit from a few pages ago were taken in the same place as all his previous pictures of his clothing, so he's probably in California.