brother and his irritating girlfriend

i haven't read any subsequent posts but this attitude is not right imo.

if they love each other and want to marry, they should and asap. your parents, unless they oppose it due to 'real' reasons, should not be prolonging this. there is no way they can islamically justify this.

yes, all involved might not be acting in a proper islamic way according to some but two wrongs don't make a right. best to make it halal asap unless they are just hoping this relationship will just come to an end of its own accord. quite sad really.

i more or less agree with Rasmalaii, your brother doesn't need your parents approval to marry her - we do this out of love and respect for our parents. if he has his heart set on her, you should help him in convincing your parents not to delay if anything.