You don't need a national television show to tell him, either go to rehab or we are totally cutting you off. Just lay it out for him.
I have a cousin that is twice removed due to his drinking and drug problems. He is currently facing a possible 10 year sentence for having drug paraphenalia and loaded weapons on a college campus.
Our family has completely cut him off. He is kicked out of his parents house, he has no vehicle, and is currently working a shitty minimum wage job for some pocket change and living in ghetto apartments or couch hopping with friends when he can't make rent.
Sadly he is still on the shit, and we believe the only way he will 'sober up' is to face his sentencing and spend some time behind bars and having to be Bubba's bitch for a while. Not that I would wish this on anyone, but everyone's choices have consequences.
He isnt the only cousin with a history of drug abuse sadly. I think the personality for addiction runs rampant in our family. My brother and I have faced our own addictions and we're slowly piecing our lives back together after we've hit our rock bottom.