[Thotmas]

You need to tell him that you are not interested in him like that! You need to make sure he understands your kindness should not be mistaken for love/affection.
The best thing is to ignore him completely until he gets the message.

I used to work with one. The security guard had a thing for me.We carried on keeping in touch after i left the place. He mistook my kindness for affection. Anyway eventually I stopped answering his calls because he was just getting too clingy. After a few weeks he called me from a different number and asked me why I was not picking up his calls, and talked as though he was my boyfriend. Anyway, I think I made it clear that my kindness was not love and he finally got the message and hasn't called me since.