"Friendly fire" is such an oxymoron. It hardly bears writing about save there are so many people who accept such moronic oxymorons.
This term is designed to obfuscate that people have no business engaging in enforcement of hypocrisy. It is what gets them killed in their iniquity by their fellow members and travelers in the iniquity of war.
This is no comfort to the family members of those lost to this insidious fire unless those family members and others see the light of the truth of it and repent themselves of war.
There is no justice in human wars on humans. Don't make war. Wage peace on war. That is the only solution. Everything else is doomed.