Why did the Audi driver chase him down? The post says the Audi ran the light and hit your friend so I don't understand why he isn't getting the driver to pay for his doctor visit about his swollen arm and/or any issues with his bike.
When I was hit because a lady rolled a stopsign I was compensated by her insurance co. They covered my medical bills, bike replacement cost, and such.
PJ
If I got hit by a car, the first thing i'd do is call the police. NOT run away. Unless maybe it wasn't really the driver of the car at fault.