How do I know If this relationship is for real?

okay so I have a family friend that I have known for ages, like years and years and before christmas he broke up with his girlfriend because she cheated on him : ( during the christmas holidays we went away and became really close and when we got back and until now we are still close, like we msg each other everyday and call each other babe, hang out a lot more and hold hands. The other night we went out for Australia day and the place that we went was filled with heaps of people he knew including his ex… when he saw his ex she was about to kiss another guy and he got really angry and almost had a fight with the guy. later he told me that he is over her but it still hurts seeing her kiss another guy right infront of him. I later told this to a friend and she said give it time but just make sure that your not his rebound girl…so what I want to know is how am I supposed to know if this is for real or just a rebound? Is it for real and he does like me but is still getting over her? am I just the rebound? should I give it time and let him make…or not make the first move? Please help : )