As stated earlier, at the time I considered suggesting he put his hands down, but then decided that I was not going to tell an adult how to handle themselves in a traffic stop as long as what he was doing was not acting in a threatening manner.
I have since talked with him and have a much better understanding of his point of view.
As a white guy, I have never worried about being shot at a traffic stop, so it is pretty easy for me to be calm.
As an African American, he does worry about it. It has been ingrained in him to do everything to appear non-threatening.
And there is no way to test other approaches without getting pulled over again and seeing how different actions might work. But when you are afraid of getting shot, you are not really in the mood to “try out new approaches”.
So it is really difficult for me to presume to tell an adult how they should behave (as long as they are not doing anything that could reasonably be perceived as threatening). No matter what I say, he is going to act in the manner that he feels gives him the best likelihood of going home safely.