Amy , You should plan a character meal on his birthday!! Make sure they are aware it is his birthday!! Also I think if you go to city hall in MK they will give him a special birthday button to wear and characters and CMs make a huge deal all day for kids with birthdays!!!
We did a character meal on my son's birthday at DL and they brought a little cake and sang and made it a blast!! Call ahead to the particular restaurant to see what they offer for birthdays!!
Also make sure you resort knows too!!!
I hope it goes great!!!