I understand your disappointment over the Pirates of the Caribbean attraction being closed for rehab. I know that WDW must rehab our favorite attractions in order to keep them running safely and in magical order, but it is disappointing to miss a favorite ride or show.
We leave in 13 days too (and Pirates is my favorite attraction)!!
For your Pirates fan, I can give you some additional ideas.
Attend Jack Sparrow's Pirate Tutorial next to the Pirates of the Caribbean attraction. This is a must see show with Captain Jack and his mate, Mack. Kids are chosen to participate in sword dueling. Once the prove themselves seaworthy, they'll take a pirate oath and receive a souvenir certificate.
The show is 20 minutes and all guests stand. Arrive early and have your son stand right up at the rope that Mack will put down near show time. There is usually a 10:15 a.m. show which we try to see as it seems the least crowded.
For more pirate info, see this
link.
In addition, you'll want to visit the Adventure Room at the World of Disney store at Downtown Disney. It is filled with pirate adventure, including an Audio-Animatronic pirate and his parrot.