Re: no backbone?
OMG…I hadn’t seen this post before.
Come on, GBL…you gotta see some humor in this. This is really immature behavior for a grown man. To even read and discuss someone’s PRIVATE conversations…is pretty LOW…let alone mocking them. I don’t think your BIL would appreciate it if you were to read and share private conversations that take place between him and his wife (your sister).
And what’s funny is that…he doesn’t seem to realize that it takes TWO people to have a conversation. So, to be fair…your BIL should ALSO mock his younger brother…because he also participated in the text conversations. 
It’s commendable…and more power to you…for even remaining polite toward your BIL. Cuz, had it been me, even if I were to be civil to him…in my mind I’d have lost respect for him.
It’s also sad that this guy even allowed his older brother to read private conversation. Would a guy like that also share details of his sex life with his older brother?
Seriously, move on. There were so many differences b/w you two (education, ambition, career)…from the get go…that a sensible person would have been wary about even considering this rishta. Having one previous divorce should not be used as the sole “common factor” to bring two people together. Compatibility and mindset need to be considered as well. Who knows? Maybe your BIL thought that it would be hard for his younger brother to find a girl to marry him because he’s not very educated or settled in his career. Maybe BIL knew that few women would be inclined to marry him…so he might have thought that getting him paired with his wife’s sister…would be more convenient. If your BIL had a daughter of his own…I think he’d be nervous about getting her married off to someone who is not on the same level (educationally, career-wise, etc) as his daughter. Pathetic mentalities are especially frustrating to deal with in family members.