Semi Truck Tips Over While Driving on Interstate

I was driving my to Poconos. I was on the interstate headed west. I was about to pass a truck driver, but he was wobbling so much that it wasn't very safe. Then right before the exit, he crashed. I called 911 right away and went outside to check on driver.He was shaking but had no injuries at all. When the cops came I gave them written statement, and showed them video from my dash board camera.