Hello dragonheart,
I'm glad Carol moved you over here, and I sure do understand your concern. You sound like you care what happens to this man, and all of us here know how hard this is.
But sadly, it is impossible to "get someone help" if they don't yet recognize or admit that they have a problem. And if it's going to require his father telling him, and his father has no intention of doing so, then you have placed yourself in an unworkable situation. You can't magically open his eyes -- he has to suffer the repercussions of his choices and decide on his own that he wants to change his life.
No one could make you want to quit drugs until you were ready. No one can make him stop drinking until he's ready.
And at that point, if he asks you for your help, you can decide whether to offer it (in my humble opinion).
What are your brother-in-law's wife's boundaries? Is she willing to stay in this situation? Does she enable him? Is she involved in Al-Anon? If not, I'd suggest it to her. Sometimes we can help more by aiding those who are willing to seek support, rather than beating our head against the brick wall of those who aren't.
Hugs to you ((dragonheart))