He's not guilty of murdering the people (since he didn't). Are you asking if not donating the money needed to save lives is murder? That's a tough one to say, because then most people are murderer's, including many of the people who are being "murdered".
Yeah you're right, I suppose we cannot assume that everyone saving lives would be the right thing to do.
I also came across another problem with this whole thing. Life could mean anything and i think that it ultimately comes down to our interpretation.
In reality it can't be just life vs. life because we cannot look at things that simple without a little bit of bias.
So we end up determining things that make one life better from our perspectives
-like age, location, chance of success of the individual, connection to us, would this person just blend in with everyone else so should I really save them, ect.