Keep reading as much as you can- the posts at the family and friends forum are full of the struggles questions and experience of loved ones.
I also recommend looking into the meditation book of Al-Anon- they have been around 70 years to help people deal With the behavior of family who are escaping their problems - they key tools and principles they practice are powerful.
Learn as much as you can and remember it is ultimately his journey- and he may refuse to face it now.
you can find productive ways to be honest and firm about his behavior And your concerns and feeljngs without being controlling or them backfiring or appearing too personal.
We have to take responsibility for what we're not responsible for.
�It doesn't matter where you've come from,
It matters where you go" Frank Turner