This is a form of child abuse.
Making him crossdress and getting to like it all because he's a 13 year old who wants attention, is a loner. He most certainly had no interest in crossdressing but did it because the sister made him feel confident while only crossdressing and it grew as something he actually likes. If she wanted to help him just hanging out together was enough. of course anyone would become to like it if they're brainwashed like this. disgusting honestly