Wow, those are some f'kd up laws from my point of view. Well, Texas have lots of weird laws..Whats the difference between "wounding" and "intent too stop" ? The whole point is to for example shot in the leg to.. guess what.. stop!
Its not so crazy, but on face value it could seem so.
There's different criteria for use of force, from only force necessary all the way up to deadly force. Guns are immediatly thrown into the realm of deadly force, (and rightly so) So, when it comes to a situation where deadly force is justifiable then deadly force is what you use. Interpretation is important here, I don't have my Texas Penal Code at work but I'll check when I go home, there was a case way back when where some goon shot another goon and maimed him, (blew his kneecaps off or something) and he used the reason you said. Because of this case the law was changed so that intentioanlly wounding, (maiming) someone is not a justifiable defense. Sounds a bit odd eh? and again, symantics come into play.
You would just need to reply to the cops and the grand jury, because you will be taken to court, (not counting civil suits - the scumbag's family is going to sue you for plugging their little angel) that you used deadly force to stop the attack which you felt emminently, (no escape) threatened your life, or the life of a third party, (wife, etc) In the process the guy either died or was incapacitated. (you're not going to be put away for being a not so great shot) but if you shoot the guy through the shoulder and you tell the cop I shot to wound the guy; when you goto court that will be admitted as evidence, and the Judge will review the precedent set in that case back in the 1800s about maiming, and suddenly justifiable self-defense can turn into intentional maiming of a victum, and you'll be fined, and then, THEN, the guy you shot will indeed have a great civil case in which he can now legally take all your shit, because you inflicted a life changing wound on him and have caused great pain and suffering on him and his family and your ass will reaally be in a sling, so you might as well just cap is ass right the first time and save yourself some trouble, because you shouldn't be too nice to theives, robbers, rapists, and murderes... You know what I mean?
That's what's in play. No one just pulls a gun shoots a robber and walks away. You'll end up with 6 months of legal proceedings to determine if you did everything above and beyond the call of duty to make sure you didn't dis this guy's rights. You'll be scrutinized 10 ways to Sunday and 100 times more thatn the piece of shit that broke into your house and tried to club you with a tire iron.
Its not the wild west, and even the wild west probably wasn't as wild as its made out to be truth be known.
Using the threat from the persons perspective in the Eilers case, if the step father was a skinny little guy, and Eilers, aknown professional fighter was bearing down on him, throwing shit and threating to rip his head off and shit down his throat and whatever else might or might not have been said, and if there was a history of violence by Eilers, It could certainly be argued that the guy feared for his life, because a professional fighter is going to be able to mop the floor with any regular guy and could kill him no?
From that perspective using deadly force, (weapon) might be justifiable. I don't know, I haven't seen the case or really read any particulars. But if someone is capable of killing you, and or you believe they have the where withal to do it, then deadly force may be justified the same as if a group of goons attack a single guy, because as a group they could kill you, hence deadly force comes into play. Basically the devil is in the details of cases like this. News stories touch on tag lines, so it tends to come across more sensational than reasonable.