Ilovespinel....
To each his own. think about this. All the time they spent on the internet, talking on the phone, they REALLY got to know each other. Sometimes more than people that meet in person, when the weird physical stuff gets in the way. Your brother had to focus on this girl for who she was.... not just because he wanted to get into her pants.
I have a co-worker that met her DH on the internet. I must admit, this is not for me...but they are happy. They never quarrel, and they have a solid foundation for each other. They are a fantastic support system and are really in love. They have been married for TEN YEARS. They have what outsiders looking in call an "ideal marriage" even though the circumstances for bringing them together... were not "ideal". He lived in FL she lived in AZ. After courting online for six months, meeting her in person ONCE, he flew home, bought her a ring, proposed, and they were married 3 months later.
I''d just be happy that your brother met someone that he loves. Their meeting may have been unconventional, however, I think when you spend HOURS really talking to someone, you get to know them a lot sooner, than a year of dates and "going to the movies" as a distraction.
You are entitled to your feelings, and I am not judging, but my suggestion would be... vent here... not there. Spend some time trying to get to know your future sister in law, enjoy being a bridesmaid... you may just see all the wonderful qualities your brother was able to see in print. Just think, us... mere strangers on the internet, you don''t care what we look like, yet we are able to bring you comfort, and listen... maybe your brother found this... in a life partner.
((HUGS!))