Yo ho ho mateys! Who says the wee lasses get to have all the fun? This authentic as they come Pirate set would be PERFECT for the boy equivalent of Bibbiti Bobbiti Boutique at Disney - Pirate’s League - where he would be turned into a pirate. 
I feel this would fit a wide range of sizes due to the construction of it - the pants are elastic waist pull on pants with a built in stirrup to look like a swashbuckling boot. White shirt is billowy and loose fitting and the vest buttons in the front. Belt/holster is Velcro so very adjustable. The set also comes with props such as a “leather look” hat and treasure map as well as Captain Jack dreadlocks with gold coins sewn right in. All he is missing is the rum (just kidding!).
Best fits sizes 5-8 (maybe even a thin 10!).