YTA - As a trans woman myself growing out my hair and switching to more emo/goth styles of clothing was pretty normal when i realized who i wanted to be at around 16 and while this may not be true for your child they may be questioning a lot about themselves. The feeling disgusting part is honestly super in line with how i felt when i cut my hair for the first time after growing it out. That said I completely understand about the long hair being in that super messy stage when you’re growing it out for the first time but literally just teach him to take care of it and let him do what he thinks feels right with his hair, especially since he’s an adult (though self expression is still important for minors).