Irrelevant.
From the Article: " When he saw Brady on the basement stairwell, he fired — then shot him again in the face after he fell down."
At the point of the dragging, Brady was already dead. Smith indeed, did not approach Brady when he was alive as you would require. You also cannot assert that Smith had ANY means of restraint reachable or even available in his home, or that it was required that he have such, except by YOU.
Additionally you assert that a 64 year old former (fill in the blank) can best a 17 year old, physically, in every case, because YOU say so.
That's real, alright.
Are you a medical doctor or pathologist??? You don't know that.
And you don't know how much of his story is true??? He might have dragged him wounded into the other room and kept him alive and interrogated him for awhile before finishing him off.
But if you are going to take him at his word, then do so. He said: "I want him dead".
He didn't say he wanted him disabled or unable to move. He said he wanted him dead.
That is not self defense. That is murder.