Nev- Maybe you could suggest to him that he do something proactive about the circumstances that are so frustrating to him. I would flat out refuse to borrow from your parents, and I would encourage H to cut out unecessary expenses like going out, etc. He isn't working right now, so he needs to not be a financial drain on you. Why not encourage him to find part-time work while he is waiting to take his GED test? Even 20 hours a week would help you guys a lot!
I don't really think he is in a position to judge you for the overdraw, because honestly (and I hope you won't think I am being needlessly harsh here) I think he is being pretty financially irresponsible himself.
You are doing FINE! This isn't you...this is his problem, and until he realizes he doesn't have to be a victim of all these circumstances he is frustrated with, his feelings probably won't change. He needs to put a lot more effort into this, IMHO.
You are doing great. I don't know how you could possibly do more. It is his turn to step up.
Big, big hugs, Myrrh
One moment of patience may ward off great disaster. One moment of impatience may ruin a whole life.