It's super hard! I found that he can't wear a small anymore...he had a small fleece hoodie and it fit well except it was way too tight around his chest because it's so deep!
It's also terribly hard to find sweaters that aren't girly! The only ones I found that weren't were this one, and one that was argyle with a skull & crossbones, but it was lime green (like the edging on this) and bright blue and orange...pretty ugly, LOL!!!