Well, I wish I was wiser than I am, just my opinion
And you sound like you are excellent support, if a little to generous,but you can never really give up on your closest family really. But attitude to change is essential, in all honesty at this stage I don't think he would change unfortunately, but if he was on some meds that work, it could do wonders. You may want to push for SSRIs, which areanti-deppresants, or somethingsimilar