I don’t know enough about racing to offer a informed opinion, however I will say it appeared that he caused his own accident. In the race for the finish line he deliberately cut in front of the driver to prevent him from passing. The problem is that the other car was pushed and he has a slower car, that made the difference.
You can see the other car went low first and Ryan jumped out in front of him to prevent from being passed. I think he misjudge the speed of the other car.
Car who hit him was teammate and was trying to help him. There is an art to the aerodynamics beyond my expertise. He looked loose to me because of hamlin...but his interview indicates he was trying to help