Your proficiency in self defense case law is showing. If shots are justified, that means lethal force is justified. It means the same thing.
Sorry to say but he's exactly right. There's no such thing as warning shots in use of force. That's something that's only in the movies because real officers are trained to only discharge their weapon when they intend to kill a person.
In fact, for everyone, even for average citizens, it's always considered an intent to kill if they shoot a gun in the direction of any other person. The law doesn't recognize an intent to wound someone with a gun. You aim and fire at someone, you're intending to kill him, regardless of where you were aiming on the person.
Now, as far as the rest goes, I'm still not sure why officer Wilson didn't initially attempt to use his taser considering be was being assaulted by an unarmed person but it's clear that the grand jury that Officer Wilson believed Mike Brown meant to kill him during the altercation. It's unfortunate that we'll never know for certain what truly happened but based on what we do know I'm not convinced the shooting wasn't completely unjustified.
I can understand and appreciate the racial tensions in this particular community but the real fact is that this kid had just gotten done committing robbery over some minor products from a gas station. He pretty clearly violently shoved the store owner which brought it up from a simple theft to a robbery at that point. Armed or not, at that point he was, in most jurisdictions, a suspect in a violent felony. It's a fact which I wish was acknowledged more often in this whole situation because Officer Wilson's knowledge of that incident demonstrates there was at least a reason for the stop in the first place. This wasn't an innocent person chosen at random off the street to be executed.
Is it entirely possible (likely even probable) that his race and perhaps even age did come into play in the way the officer chose to engage him? I'm willing to bet so but I'm starting to believe the seemingly false eyewitness testimony of Mike Brown essentially being summarily executed is what has tainted the view of this case from day 1.
The more compelling story of the situation is whether Mike Brown was attempting to surrender at any point in the incident. If he was shot even after attempting to surrender, well then that's an entirely different scenario. Unfortunately, there seems to be little evidence to establish in either direction.