It is very difficult to find a dress that fits my slim 11 year old daughter. This (and other CC shirts I've found on Ebay) fit perfectly! He can tuck it into his pants and it won't be too bulky, or he can wear it loose with a nice pair of jeans.
The Good Day Lab Clean Shield: Ultimate Comfort and Breathability in Tagless 4-Way Stretch Polo
43 Review
Van Heusen Sleeve Dress Poplin
42 Review
π Hanes Boys' Short Sleeve T-shirt Value Pack (3-pack) - Essential Wardrobe Basics
44 Review
Boys 3D Graphic Hawaiian Aloha Short Sleeve Dress Shirt Tops with Button Down - Sizes 2-8 Years by Uideazone
47 Review
π Bold Pack Sleeve Active Hoodie Sweatshirt Set for Boys' Clothing - Stylish and Comfortable!
47 Review
Boys' Adidas Active Sports Tricot Athletic Clothing
45 Review
Waterproof Cozy-Dry Rain/Snow Pants for π§ Kids by JAN & JUL, with Fleece Lining
64 Review
Arctix Youth Pants Reinforced: Large Boys' Clothing for Active Adventures
46 Review