Help Guys why is he doing this?

He showed clear signs he liked me...he's my brothers mate and family friend,he use to come to my house every saturday to pick my brother up for snooker, he also does lottey syndicate with my mum, from my mums phone leaving my name i causually text him the lotto num, i got no reply. Ever since i text a casual message, he stopped coming to my house...he avoided family dinners,and now this time he had to pick my brother up he collected him from outside, didn't come inside usually he comes to say hello. He's not avoiding anyone else but just me. Why is he doing this, i also suspect my friend dating him behind my back...she knows dam well how much i like him. This is killing me from inside :(