"Accidentally" as in he did not purposely shoot her?
Or "accidentally" as in there was a mechanical malfunction of the mechanism that would have rsulted in the firearm discharging regardless of how it was handled?
Does anybody remember why there are three (3) rules* of firearm safety? So that even if you violate one it is unlikely that something bad will result. Violate two and there is still a chance that nobody will get hurt (except for their pride and their hearing).
* - Of course all firearms are loaded. Or they should be. Unless I am willing to bet my life on your safe gun handling (which I will be doing) I will unload a gun before passing physical possession on to another person. I will also check to make sure any gun passed to my physical possession is loaded so that I know it is ready for immediate use. When it comes time to handle a firearm for reasons that do not involve shooting it I will unload it because those cartridges seem to get in the way of all sorts of stuff - cleaning the barrel is a good example.