Guy's Behavior

Guys, Why is he so cautious around me?

There's this man who is about 10 years older than me and he always acts different around me. He likes to ask me questions like how are you and what is up. Which you're probably thinking that's normal, but it's unusual of him as he doesn't ask other girls this. He seems scared, worried, or protective when he asks them. I thinks it's because I'm a shy and closed off person that he needs to know I'm okay. I only give a one worded response most of the time and then he just leaves it at that and walks away to go on his laptop or phone. Also when were in large groups I'll catch him staring at me and I'm not the only one who notices. He makes very prolonged eye contact with me as well. I am a dominant but shy and approachable person so why is he so cautious around me? I have to be close to this person so I would like to understand this situation (And no he doesn't like me in a romantic way, he knows I'm ace as well).
Guys, Why is he so cautious around me?
Post Opinion