What do I talk to a guy about who has been acting weird around me?

Hi, I asked a question on yahoo answers before about why my used to be best guy friend has been acting weird around me. His eyes dart everywhere when I look at him and he has changed his appearance by changing his hair and wearing lynx. There is this girl that he is friends with and she flirts with him a lot. She ruffles him hair and plays footsie with him. He looks really uncomfortable though because he backs away when she hugs him and always looks at me weirdly when she does it. I think she is trying to make me jealous because I was his best friend. And she always does it when I can clearly see them. His friends look at me in groups and smile while he looks at the floor. He sometimes ignores me as well but not like full on ignoring. I am lucky to even get a sentence a week of conversation . The answers that people gave me from my other question were saying that he likes me and is nervous because I was his best friend. They were saying to try and talk to him more often because he wants to be more than just friends. I was wondering what are good conversations to have with him because it will be really awkward , what do you say to your friend of two years who you have drifted apart from? I get really nervous in conversation as well. Thx for reading this. :D xxx