ADHD blankets way too many things these days. Not saying he doesn't have it, but it sounds like more. I have an uncle with ADHD who starts a million weird projects around the house he never finishes and can't function or keep jobs because of his lack of focus. He doesn't hide from his family and act hateful and angry. Your husband is displaying JD- Jerkitude Disorder (selfishness, lack of being able to understand or care about the feelings of others-being pissed off because he's out of work-I'd be SHOCKED to hear he had two awesome parents who instilled responsibility and generosity in him) as well as MAYBE possible mental illness with a twist of ADHD, but I'm not really seeing the ADHD, but I'm no doctor and the diagnosis doesn't really matter as far as what you should do. Also, in a home with one parent acting like this, rather than a calm, supportive structured environment with two sane people working hard to raise the kids and putting them first, you daughter's issues may not be 100% an inherited neurological disorder either. But again, I'm no doctor. I'm only commenting on it at all because you seem to be focused on coping with ADHD in your mail, and I don't think that's the point.
There are two hard paths you can take, and no one will judge you for either one.
If you want to stay with your husband because you love him and can't picture life without him and think your kids need him, then you have to show him tons of love no matter how he's acting. Give him treats, find his good points even if there are none, stroke him, make him the king of the house for a designated amount of time. It will be the hardest thing you ever do not to fight with him or show your own hurt and fight for your rights at first, but over time-maybe 6 months, he can't fight against a force who isn't fighting with him, and as he feels better about himself and trusts you, you can start to encourage improvements in him in non threatening ways. It's a long hard road-I have a great book if you want it.
Option two would be to lovingly offer him the opportunity to have life without you guys because he doesn't seem to love you. You should put it to him like that, because anything you say in anger or even in sticking up for yourself, will be seen as an outrageous offense in his selfish eyes, and he'll blame you for any and all difficulties resulting, including hurting the kids. Tell him you love him, and you see he isn't happy. Tell him you think you should try separating because the house isn't healthy for the kids and HE may be better off not having to hide from you guys and finding a world more up to his high standards (try to be sincere).
Maybe in an attempt to keep you guys, he'll be more open to seeking help if he sees he can't keep the status quo where everyone is hanging around bugging HIM. Maybe not. Then move on, sister, start from scratch. You can do better and your daughters deserve a happy home. There is no easy way-bless you for the trials ahead, we're all pulling for you and you're not alone.