It’s a college town, though far from Chicago and Springfield. Near the aouth of the state.
It’s not likely, but you’d have to check the gun sanctuary county map for the state. Many sheriffs are refusing to enforce IL’s gun control laws. He might have a chance if it’s a 2A sanctuary county.
If hey/they are still advancing, at 20 feet away or less you start shooting to cripple or kill. It only takes a second for them to cover that distance..
If they stop, you keep on covering and warn. If either going away, you still cover, but do not shoot the one stopped or receding.
In this situation as described, the defender was way past the warning stage, and completely justified in deadly defense of his person from either of the attackers. They clearly both demonstrated their intention to harm him.