Why would a guy keep staring at me even though he knows that I know he’s looking but he also tells everyone he’s shy?

So there’s this guy at my workplace. I once confessed to him, but he said he was too old for me and that our age difference wasn’t suitable. After that, he didn’t reply to my message. But ever since then, the way he treats me has become closer. He often asks about me, he opens up about feeling lonely, but he has never actually confessed anything to me either.

Sometimes he’s extremely protective around me, and whenever we have to work together, he’ll treat me to food. He also once almost got engaged, and since then he’s been single for almost 10 years.

So I’m wondering… is he just a very shy person and who doesn’t know how to open up their feelings?