In the first Harry Potter movie, their is a statement that while it takes courage to stand up to your enemies, it takes a good deal more to stand up to your friends. The same can hold true for standing up to family members.

I have a brother that was physically abusive to a g/f that was a friend of my g/f. My Mom tried to play it off like it wasn't that serious, and then she says, "Blood is thicker than water", meaning I should stand up for my brother. I simply told her that he did something wrong and I could not stand up for him. I could support him in getting help or counseling, but I could not enable his abuse behaviour.

I think if you have to trade the wrath of your parents in exchange for your brother getting well, then you should. Your parents will get over it eventually. (Hopefully) Some times you have to do what you feel is right, regardless of what your parents think.

Good luck!

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Put me on wheels and I'll turn tricks.

Clever? Nah, I ran out of that years ago. But if you find this, let me know, k?
"The road goes ever on..." ~ Tolkien

In memory of my friend skip...
Go then, there are other worlds than these