Autistic kid likes me?

Okay so I'm in grade 7 and this disabled boy in grade 6 (i'm pretty sure it's Autism, but not 100%) has a crush on me. He told me he had a dream about me, it's trying to get me to wear matching t-shirts with him, and is following me. Even during cl he comes in and says hi. I have nothing against his disability, it's just that I don't like him that way, and he is starting to scare me. I want to let him down gently, because he is very sensitive. I also don't want to tell him, "We can still be friends", because he will think that that means to hang out with me and my friends every recess, and we have nothing in common. I don't want to sound mean, I just don't know what to do. Please help, and thank you .