Why would a guy be so nice to me?

so i have a coworker who does a lot for me. When im working, usually carrying something heavy, he takes it out of my arm and carries it. Two times i have been assigned two projects to work on, it wouldve took me 30 minutes to do each but he helped me and did it under 7. He will only help me and no one else who i work with. We are always around each other and other people see it. A coworker even asked if we were dating. He's a little bit older than me in his 40s while im in my 20s. He has flirted with me in the past but now we are just friendly towards each other. We only speak at work even though we have each others numbers. We work two different departments and he's really not suppose to be helping me and will get in trouble if caught but does it anyway. He even offered to get me something to eat.

Why would a guy be so nice to me?
Post Opinion