Guy's Behavior

What does he mean by "Hey girl?"?

Long story short. We were new friends. He was a transfer at our university. He had a GF back home, so things were always platonic though we had 4 classes together and I'd give him a ride every day. Feelings started to develop. He would stare at me in class to the point that it was ridiculous. Only talk to me, mostly. He was shy. He would never hang out with me when I invited him to group functions. He broke up with his ex. Poured his heart out to me. Said he never got close "to anyone" for fear of cheating on his ex. Sent mixed signals. Said he wanted no one but her but that he wished she was like me. Left looking disappointed after that. He always called me "friend" in texts, though I never hinted at more... it was always him sending signals, then calling me a friend. He wanted to make sure we'd hang out again next semester. Complimented me on my looks like always. Told me he'd text me this summer. Never did and got back with his ex. They broke up a few weeks ago, right before school starts.

Knowing he's single and missing him, I sent him a light, playful text: "Where is your crazy butt?" It was move-in day today, so I assumed he'd be in town and I wanted to see if he was coming to the concert. He texted me back, "Hey girl I'm in *insert hometown* How is everything?" I said, "Boo! You're missing out! Lol." I sent him a video of the T-Pain concert with the message. He goes, "Damn that looked fun."

My thing is... maybe I just read everything (that I couldn't include here) wrong over the course of our friendship and he never felt the same? Calling me "girl" and "friend" seems distant and like a boundary. My guy friends said he was sending so many signals when he came over after dumping his ex, but I wouldn't throw him a bone. But, how can I throw a bone to someone who sends mixed signals?
What does he mean by "Hey girl?"?
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