@2ND if a male be androgynous enough to pass as a girl in a hoodie, he can use any wide enough fitting shirt, though I assume a sweater like a hoodie hides better one's complete lack of mammary development.
I think he's trying to reclaim his masculinity with the hoodie. A mean, ponytails aren't gender specific really, they came about because they're good for combat and making sure your helmet stays on or that it doesn't get in the way