Family of armed robber outraged that store clerk shot and killed their brother in self-defense: 'Yes, he's robbing them — oh well!'

[Derec]

Cool made up story bro that misses the point. Suppose the victim falls down and the robber trips over him and crushes his skull. According to other cool story, this makes this possible deadly force.

That would be felony murder. When a death occurs during the commission of a felony, whoever committed the crime, can be found guilty of felony murder, even if the death is an accident.

But you have to have committed a (in many jurisdictions violent) felony (such as robbery) for that rule to kick in. If anybody gets charged with felony murder, it would be an accomplice of the dead robber.
Take this case.
Teen turns down plea deal for 25 years in prison, gets 65 years instead

In a two-day trial in March, Lakeith Smith, now 18, of Montgomery was convicted of felony murder, burglary and theft for helping in the 2015 break-ins of two homes in Millbrook, about 10 miles north of Montgomery. He did not kill A'Donte Washington, 16, of Montgomery, who was part of a group of five accused in the thefts.
But several in the group, including Washington, fired shots at Millbrook police officers who responded Feb. 23, 2015, to a call of a burglary in progress, according to officer body-camera footage. The officer that Washington ran toward pointing a .38 caliber revolver fired his police-issued sidearm four times, killing Washington.

Little twerp should have taken that plea deal and he would have probably been out at around 40 at the latest, but probably much sooner because of parole.

Smith smiled and laughed through the sentencing, said C.J. Robinson, chief assistant district attorney. Smith flashed a broad smile March 14 as he was led out of the courtroom shortly after the verdicts were announced.
I don’t think Mr. Smith will be smiling long when he gets to prison,” Robinson said. “We are very pleased with this sentence. Because the sentences are consecutive, it will be a long time before he comes up for even the possibility for parole, at least 20 to 25 years.”

As I said, little twerp.

"The officer shot A'donte, not Lakeith Smith," Smith's lawyer, Jennifer Holton, said during the trial. "Lakeith was a 15-year-old child, scared to death.

Kind of hard to buy the "child, scared to death" story when he's been burglarizing houses and with a crew that carries guns and has no scruples using them against police.

He did not participate in the act that caused the death of A'donte. He never shot anybody."

He most certainly did "participate in the act".