Like I said read the Texas penal codes 9.41 thru 9.44 . If you don't believe that read about the Joe Horn shooting incident in Pasadena Tx a couple of years ago.He killed two guys who burgularized his neighbors house while he was on the phone with the police and was nobilled end of the story.
Like I said above, Texas is way out in front in their laws on this one.
But, please note, this did
not go down in Texas and as far as I know there are no other states where this would be justified.
If the information in the OP is true and that is what the DA and the jury will see then this guy is going away for a while.
