The eighth-grader is clinically brain dead and being kept on life support to harvest his organs, attorney Mark Nation said.
When Ralph Penley arrived at the school Friday to help police and school officials defuse the situation, he wasn't allowed inside, Nation said. (Watch Nation explain the father's frustration -- 6:55)
Nation said Ralph Penley was "angry" because he had spoken to police before he arrived at the school and told them Christopher did not have a real gun. Christopher's younger brother told school officials the same thing, Nation said.
Asked if the father blames police for his son's death, Nation said, "I'm not here to point a finger at anybody at this time."
Seminole County Sheriff Don Eslinger said one of his deputies shot Penley only after the boy threatened him with the gun, which had been painted so it would look more real.
One of Penley's classmates said he, too, thought the gun was real -- and that Penley was going to kill him -- until he grabbed the pistol and realized it was fake.
The ordeal began about 9:30 a.m. Friday at the 1,100-student Millwee Middle School in suburban Orlando, Florida.
Maurice Cotey and his classmates were about to take a test when two students noticed the gun in Penley's backpack. Cotey heard one of them say, "This kid has a gun." (Watch the aftermath of the Friday incident -- 1:54)
"The teacher, she went to the phone and told the office, and then he, the kid, he went to the lights and turned them off" before pulling the weapon and showing it to the class, Cotey, 13, told Orlando's WKMG TV.
At first, Cotey thought the gun was fake, he said, but Penley "seemed so sure that it was a real gun, so it like scared me, kind of."
Everyone darted from the classroom except Cotey and a girl, he said. Penley looked at Cotey and said, "You stay." The girl ran out.
With his gun in Cotey's back, Penley told his classmate to get against the blackboard. Cotey began pleading.
"Please don't shoot me, please don't shoot me," Cotey recalled telling Penley, who ordered him into the closet.
As the two walked toward the closet door, Penley grabbed Cotey and turned him around, and Cotey seized the chance to try to wrest away the gun from his older classmate, he said.
"He started to point the gun at me, so I started to grab for it and he pulled it away," Cotey told WKMG. "And then I grabbed for it one more time 'cause he pointed it at me for like a little while, so I grabbed it and I twisted it and I pointed it at him."
It was then that Cotey knew for sure the gun was a fake. (Watch Cotey describe the frightening ordeal -- 1:33)
"While I was twisting it, it started to come apart like a toy gun would, like a dollar-store type toy," he said.
Cotey pointed the gun toward Penley's legs, but Penley kicked him into the closet, the 13-year-old said.
Cotey was able to get out of the closet and run out of the classroom. Penley already had gone and was running from a school resource deputy and others who were chasing him, Eslinger said.
As he ran, Penley could be heard saying, "I'm going to kill myself or I'm going to die somehow," according to Eslinger. At one point, he held the gun to his neck, another time to his head.
Penley fled to an isolated alcove area and went into a restroom where he refused to speak with negotiators, the sheriff said.
Authorities pleaded with the boy inside the bathroom to put down his weapon, Eslinger said, but the boy refused.
"He refused to even comment. All he said was his first name. He did not drop the firearm," the sheriff said.
Finally, the boy came out of the bathroom and "raised the firearm in a tactical position and pointed it" at a SWAT team member, who "decided to use deadly force," Eslinger said. (Full story)
The boy's motive was not immediately clear.
After the shooting, deputies discovered what Cotey had suspected -- the gun was phony. It was an airsoft pellet gun, and the normally brightly colored tip had been painted black to make it look more authentic, Eslinger said.
Such guns generally shoot plastic pellets or paintballs.
In a news conference after the shooting, authorities displayed the gun alongside a real 9 mm handgun. To the naked eye, there was little difference between them.
"It was a terrible situation," the sheriff told reporters.