
The idea that someone would force someone to change genders is actually more horrifying to me....The dad could have simply asked him to cross-dress to try it out first to see if it was something he really wanted... So like are they referring to the brother/sister as a she or he in this manga? If it's not what the sibling wanted, can't they change back?

Well I’m not very knowledged in that area but I think that if he went full transition, like bottom and everything, I would be quiet hard be change back and even if he/she did I wouldn’t be the same as before, also seeing the way they live I don’t think they have the money for if, the dad seems pretty rich so he must have paid for everything
The misgendering of the older sister makes me sad