Hi Sasha, most likely you were right about this gentleman. I have been seeing things like this all my life. Most likely the reason for the shaking was a slight fear of the "unknown." I have not had any fear since I was very young with any spirits I have seen. I have never picked up on any that could harm me. Some can be "grumpy" as I call it though. The one thing they all seemed to have in common is they wanted some help.
I have found if I just tell them it is okay for them to use my light to cross over most of them just go. They are drawn to us because we are a beacon of light to them. Some just need help to know it is okay to cross.
I hope this helps some. Dan : )