why does he act like this and no express his feelings?

I have had a thing with a boy for two months. he is very good at tennis so he is gone a lot or playing a lot, so I understand it's hard to text me that much but I had to tell him to talk to me cuz he once went 6 days without texting me. after that he now texts me everyday but the convos are short don't go anywhere and are pointless. he has never told me how much he likes me or like how pretty I am and just seems nervous I guess around me. I like him a lot but for this relationship to proceed he needs to text me more and be more flirty and boyfriendy and show how much he actually cares:( what do I do? ( I know he likes me cuz we have talked about how this is a thing btw)