Thank you all for the replies.
Finally I talked to the man at length and it seems that he sees nothing but that for the past six months or so he has had problems he thought were physical like the sensation of being bumped poked and hit at times and he said he has felt very sick on and off.
He seems to think that if it's anything its some kind of poltergeist. He also said that if he didn't have the things going on that he does he would have thought me insane and spent some time thinking about what I told him before he came to talk to me.
I have had a camera on hand but so far there has been no opportunity. The man made a good point that if he cant see them he doubts a camera can. I didn't know this but he is a professional photographer.
I'm not familiar with any of this but I am researching what I can, this has been a life changing event for me, it's not every day that you start seeing things that no one else can and aren't supposed to be there. I still don't believe in this stuff but I believe what I'm seeing and I believe what this man is saying.
I found this message board doing an internet search so it's kind of all new to me. I have looked around - pretty crazy stuff.