Obstacles to overtaking

Hello, today I met a very “special” driver on a cross-country trip. The situation was the following: Inner town, a little busy main road, I at 50. Bid me a right turner (with advance notice) and hardly comes from the spot. I want to overtake him, he drives to the right shows me the bird and, for no apparent reason, kicks, like a crazy on the brake. If it had crashed, what would have happened? can someone say, how there the police would have distributed the blame e? after all, he drove out and then the disability and the action with the brake. I also noted his license plate, can you do something else? Greeting P.S. I hope I wrote in the right forum, otherwise please move