He's willing to stand up to you.. He has his family to run back to... He likely saw his motehr when you were crying and the man in him actually came out.. he WANTS to say this to his mother most likely but can't...
He CAN to you... that's a very different dynamic.
The contacting his sister isn't to get her to talk her her brother, its more to make a point to your H that you dont' despise his family, simply that you woudl have more respect for him if he was willing to act independent of his parents
His sister does sound like a mess, but taking her out to a lunch or something 'on you" may say a lot... it may even earn her respect at the very least...
Right now your H is turning this into a war of you vs teh family... befriending his sister would throw a wrench in that...
