Wait wait. If they’re siblings I understand sharing clothes but... she’s insanely bold! I don’t think even a girlfriend would do this unless they’re extremely close. It’s like putting in the same used pants. It’s fine for siblings but for a stranger... Lol.
On the other hand, it’s because she’s a girl that he can’t use it. If it where a guy friend it’d make sense. Her logic is “You’ll accept other guys but not me” it’s because your a girl, duh lol