Re: Brother has had sexual contact with sisters - what now?
i’m sorry your world is so small 
if you seriously think crimes of this nature don’t happen in asian/muslim countries, you’re deluded. it is probably far worse but is so shunned in society that the victims are too afraid to come forward. just because crimes of this nature are prosecuted in the west and it becomes common knowledge, doesn’t make it more prevalent. as for porn, it’s a multi-billion dollar industry the world over, including pakistan and india.
as to the OP- shunning your brother will resolve nothing. he needs help, counseling, treatment and guidance. what he did was wrong but locking him up and throwing away the key isn’t acknowledging any of his issues that made him do what he did. and he needs that. you need to stay where you are and figure this out because your mother seems absent from these conversations, your father is over-emotional and unable to think logically, and your poor sisters cannot be expected to feel anything but revulsion for him and rightly so. as completely and utterly wrong he was, and as horrific as the situation is, he needs help also, and since you seem to be the only one capable of providing it at the moment, it is your duty to do so instead of going back to school. whatever happens to your brother from here on in, good or bad, is as much your responsibility as it is your parents’.
have you taken any steps to contact therapists, psychologists, or treatment facilities?
redvelvet is absolutely right in her previous post. no one is born with this kind of evil inside them. perhaps he was abused as a child, perhaps he was in the wrong company, none of these justify his actions but its clear he needs help. get him the help he needs, and look after your sisters’ well being too. its a lot of pressure and a lot of work for you but there isn’t anyone else apparently who can step in.