What is his deal?

Megan
I was hanging out with my boyfriend/fwb last night until he got a call. His "sister" had a seizure and he had to leave to go to the hospital. We got dressed and then he had to take me to my car. He kept saying that he was sorry and I told that it was ok and he said that it wasn't. After awhile he text me updates on his "sister" and said that he felt like an ass. I later found that this most likely wasn't even his sister. I knew that she lived in a different state and I saw that she posted something on Facebook the day after and tagged her location which in the place she lives at the moment. I think this other girl was possibly his girlfriend because I did hear some of the conversation he had on the phone with the person. But if that was his girlfriend why would he be upset about having to leave me?