Special needs friend who has a crush on me wants us to kiss at his birthday party in about 12 hours.

So my special needs friend is having a birthday party tomorrow.  He says he doesn't want me to get anything for hid bitrhday but wants us to kiss. Thank goodness it was in a text that he sent.  I said I'm not there yet.  So what if he tries to kiss me at his birthday party?  What should I do?  Ruin his birthday by saying no or saying no after his birthday and breaking his heart thinking we had something?