Prison?

I read somewhere that Hirayama may have been in prison. It is never said, but it would explain why he appreciated the simple things that we all took for granted. Hirayama took time to enjoy nature. He also enjoyed his routines like going to a bar, reading and listening to music. A person who would have been locked up would have had all his freedoms taken away and his movement restricted. I also got the vibe that there was a family rift that had not healed. His reactions with his sister hinted that all was not well.