Hello Kay! Welcome back to the Disney Parks Mom´s Panel.
I can also suggest letting your son plan all activities on his birthday, so that he gets to enjoy his favorite meals and attractions. Still, you let him know that there is a special activity taking place at certain resort and time.
For that special activity
Disney´s Specialty Cruises may be a magical experience for your son. The entire family will be able to relax and enjoy a pleasant evening on board an elegant and comfortable boat.
Guests can upgrade these cruises in different ways, even making it a celebration dinner and cake, while watching Wishes or Illuminations fireworks show.
When at the parks and restaurants make sure that all Disney cast members can notice that it is his birthday, this is a great way to receive special attention and possible surprises. This will also help when you ask a parade cast member to include your son in the parade.
Happy to help you plan a memorable Disney vacation to celebrate your son 18 birthday.
Miguel