What does he think "being a girl" actually is?
Does he realise that he can't "be a girl" because he doesn't have the internal structure of one? He never had periods that started when he was not out of childhood, had to take sanitary products to school age 9 and dread changing a pad in the loo because of the sound that everyone heard, and be scared to death of leaking blood every month because you had to do PE in tiny shorts that showed your knickers. Does he realise that he is lucky never to know the cramps that almost disable you every month that ruin your life for days/weeks? The hormone that dictate your life?
Does he know the embarrassment of having bosoms at 10 years old before anyone else. Hiding in the corner of the changing room because everyone is seeing your bosoms and you just want to cry at being spotlighted as "developing"???
Does he know that as a "girl" you are a target for men to look at/ appraise and sneer at if you are not "up to their standards"?
Will he ever know the pain/worry/hormonal and physical changes that happen when you are pregnant and give birth? The feeding of a baby when it feels as though hot needles are being put into your nipples, but you carry on regardless because you are a mother?
No, no and no again.
Putting on a frock and slapping on a bit of lippy does not make you feel like a girl. He will never know what it is like.
Please dont pander to this stupidness @UndertheCedartree . He obviously needs help, but he is not and will never will be a girl, simply because he is not and never will be one so cannot possibly know what "feeling like a girl" ACTUALLY is.