He's making it sound like Kastouni was an innocent civilian bystander, just minding his own business.
Yet at the same time, Al Jazeera issued an obituary of al-Kastouni, saying that he has been a "fighter since childhood" and says explicitly that he had a weapon and was engaging in battle when he was killed.
It also says he has been throwing firebombs at Israeli soldiers since he was a child.
I don't think even the ICC would find Israel guilty of shooting an armed man who was shooting at them as they attempted to arrest his brother.