Why keep talking to me if he doesn't want to take it any further?

Ok, I need your opinion. This guy who is a friend of my mutual friend gets my number from my website and texts me in July to spend his bday w/him. So we did and had a good time. Problem: This guy is good friends/buddies w/my dad and my dad's best friend, so he is scared to take it any futher just incase it doesn't work out (from the mutual friend). He dates this other girl, pretty sure of it, but he still calls me even though I don't know him very well and just started talking to him in July. He used to ask where I was, tell my Dad to tell me hey, and ask if I was going to be at something. So he called me today and I just feel like we are both attracted to e/o and like each other, but I feel like we are stuck in this just calling e/o thing. Oh and the other week when he came up to meet up with some friends at the mutual friends house he hugged me (nobody else) and like rubs my back when he hugs me...BUT, he barely spoke to me! Like it was so awkward! So what do you guys think? Likes me but not wanting to commit since he is dating someone and the issue w/my Dad? Doesn't want to let me go though? I just need answers about what you think is going on w/him/what he is feeling and what to do? Just stop answering his calls? I feel bad not calling him back though. Like he calls me about every week and a half and then we have these great conversations, but then the other week he just hugged me and barely spoke to me w/his friends around. QUESTION: I feel like it's going nowhwere, but why keep talking to me if he doesn't want to take it any further? Help please!