Han had kept himself apart from this crazy city. What his daughter had told him had been enough to make him deem it smart to keep the hell away. His ship was his getaway, and he had more than enough rations to wait out...whatever it was that was going on. So yes, Han Solo was not being a hero today. He was doing the smart thing and keeping out of it.
Then his son and daughter showed up on his door step.
Han took one look at them, and didn't bother thinking. "What happened to Jaina?!"