Face it. The kid did not enter the house nor did he demand anything. The old man shot him through the glass because he was scared and then he opened the door and shot the kid in the arm while he was on the ground.
Yes, I can face possibility that it was a bad shoot.
If all of the facts you cited turn out to be true, there is no question that it will be a bad shoot.
Every one of those "facts" has been contradicted by early reports. But I do know what they say about early reports. Later reports seem to be firming up. I am still looking for the unredacted police report.
Things don't look good for Lester.