The "victim" probably should have asked his lawyer about how his online communication might affect his case. He makes himself sound a lot more like someone who plans to shake down the rich and famous driver than a hapless "victim" of a ruthlessly uncaring monster. A jury looking at some of those comments might not be so sympathetic.
The incident does underline the need for the driver to engage police early in any accident involving possible injury. Any accident can be so characterized after the fact and following a visit to a plaintiff's attorney. The driver in such cases can be in a bind. If he depends on the word of the victim that there is no injury, he can find himself charged with leaving the scene of an accident or failing to render aid in addition to the adverse appearance in a civil suit. On the other hand, he has no way to make the victim accept aid or even any practical way to keep him on location while the police arrive. The safest move would be to summon police and file a report on the spot, regardless of how insistent the victim is that he is fine. Figure you are betting the loss of an hour or so of your day, and a hike in your insurance premium against a potentially devastating damage award or criminal jeopardy.