I wouldn't be so sure about that. For one, he killed one of the most beloved lions in Zimbabwe that was kept on a nature preserve, without a permit. Plus being from the US there is the matter of international law, but I doubt the Fed's will really want to help him that much since yeah, they could give him a stellar legal defense, but for what? Creating a unnecessary sour spot in diplomatic relations for a reckless moron, enraging animal activists? Hell no, they'll give him sub-par support at best.
He's probably gonna be charged to the full extent of the law since circumstances are so damning. Not to mention as word spreads his dentistry will go down the toilet.
The law likes to screw people for circumstance, less for morality, and here it works.