What should i have done? 15 points?

I was driving in the highway and there was no cars. I put my left signal on and at the speed of 60 miles per hour i was gradually changing lanes. As i look to the rear view mirror, there was a black speedy car from afar. I was still in the process of changing lanes and the black car zooms so close to me. He tries to hit the side of the car and speeds right in front of me. He suddenly stopped the car and i had no time to press the brakes so i turn right and stopped. I was so scarred and shocked how the guy wanted me to hit the front of his car. It seemed as if his motive was to get money from insurance. As i was trying to take the license plate, he rushed through speeding. He could have killed us and not to mention we have a baby in the car. Thank God i turned right or i would have crashed him and thank God the person to my right was so generous to stop because if i hit her, it would have been my fault and if i hit the back of the crazy persons car it would have been my fault. How can one prove that the crazy guy suddenly stopped in front of me in order from me to crash it. I was unable to stop my brakes completely. Was there a way i should have done that was legal and cannot get in trouble with the cops?