I sent him plenty of emails over the years, letters, carefully worded. He never got it.
I had to write a letter the first time he went to rehab - an "impact statement" if you will.
Driving him to rehab - the first time - he was completely blacked out. He wasn't remembering that he'd just eaten, was ranting about all sorts of stuff, and it was the first time in my life I'd been scared of him. At one point (granted, this was a 3 hours drive) he started in about how I didn't appreciate what he was doing for me. And I ripped into him. I ranted about all the stuff he never did, how he should be grateful for ME, and I used the exact same language back at him.
It shut him up for about 10 minutes, but damn, it felt good to get that off my chest. Of course, he didn't remember it, but it felt good.