I haven't read your other posts, so forgive me if I'm not taking everything into account. I have several thoughts and questions.
1) What about D18? Does she live with or near you? Could she watch her younger siblings once in a while so you can get out of the house?
2)What exactly do you want from H? It seems like there are more issues than him merely being a WA. If the issue is only that he is depriving your children of having a father in their lives, then your decisions become clearer (and easier, I would think).
He is NOT a good role model right now. I know you fell in love with him at one point, but the reasons you did were not neccessarily the same reasons that make one fit to be a good parent. I would think seriously about sending them off with him by himself. Again, I don't have the whole story, but if he's as irresponsible as it seems AND a hustler by nature, that is not a healthy influence. It would be better to be deprived of his influence than to be poorly influenced by him. You seem like a hard working, loving and responsible person. Let that fill the void.
Furthermore, if there are these immigration issues, then I assume he is a foriegn national. It would be a tragedy if he returned to his country of origin with the kids. It might be near impossible to repatriate them legally. So that would also give me real pause.
Again, if this is the only issue, I might be inclined to use EAP legal services to draft an immancipation for the kids from him. I'm not a lawyer, so I might not be calling it the right name. I think sometimes they call it waiver of parental rights. Make him sign it and be done with it. If he's not working, you won't get any money out of him anyway. Later if he grows up and starts being responsible, you can always decide to let them see him at your discretion.
As far as the codependance, I know you've read a lot of posts and the books. You have heard lot's of others say how much letting go and GAL have helped them and their outlook. it has worked for me too. Eventually, you start developing self respect and understand that there are things you aren't willing to put up with (boundaries). It sounds like you're on your way. If you can't get out of the house, then spend a lot of quality time with the kids. To me GAL means get the life you want. I like spending a lot of time with my boys, so that's a big part of my GAL. I take them on weekend trips. There's a lot of free stuff to do that is fun and exciting for the kids.
Keep working on you!
Good luck.
ADAPT. OVERCOME. IMPROVISE. -Tom Highway
Me: 43 W: 40 S12 & S9 Married 17yrs Together 20yrs