I need some serious help! Boy issue!?

Okay here it goes, so my aunt is married to this guy Henry and his little brother (my age) came up to live with them for the summer. This kid lets say his names Kevin lol, well he just got contact with me on facebook. So i was kinda excited because hes my age and we might like each other after awhile so...he asks for my number cuz his computer froze and we were texting and then..he sends me a picture..and im thinking well maybe he wont look that bad but i open the text and..umm well hes not very attractive, to me. Usually idc about looks but I can only go so far. So now hes like constantly texting me and ending every sentence with a smiley face. If this was just some other guy I would delete him from my contacts and move on, but this is my UNCLES BROTHER! I cant be mean. But then again, Im not that good looking either so maybe once he sees me he will back off:P Please help me on how to handle this!