As with most of these things, Walmart will offer a settlement to the guy's family and they'll eventually reach agreement - particularly given they are from Haiti and will most likely see an offer that most of us would consider an insult to be a gold mine. It's a shame, but that is the reality of this sad event. Money talks.
I can see the argument that Walmart bears responsibility. But still, even if the crowd was a tsunami that couldn't stop they knew what happened after the fact, and many still went on to shop and then threw fits when they kicked them out of the store and closed. They may not be criminally liable but they ought to bear some shame for their overall conduct - before, during, and after.