On S, he might be growing. Sometimes growing either makes them sleep more or less, and in your case could be less.
I think you just need to sit down and write to yourself in a journal what your last straw is. For example, H is making progress slowly on the depression, but making a boundary for the drinking will be good. Also honestly going to a alcoholic's family meeting could be helpful. Even if he isn't an "alcoholic" some of the suggestions could still be helpful and maybe they can help you talk to his parents about enabling and being part of the solution instead of helping him.
You are doing great and if you get a chance (I know there isn't much due to S and tax season), but take even an hour one night to do something you want to do to rejuvenate yourself. Even if it is just a long bath. Do something for you.
Me29 S3 H left 4/1/09 I file 8/2/10 Divorce final 5/17/11 1st http://www.tinyurl.com/25lhu52 2nd http://www.tinyurl.com/2c35ueg 3rd http://www.tinyurl.com/322yk89