Kate, it sounds like you're doing it really tough . I have to say, I think the problem is solely with your DH, and that is what you need to address. I don't know him, so I don't know how you can do that, but he has GOT to stop all this nonsense, and undermining your parenting, particularly right in front of the kids. He is not their brother, or uncle, he is their parent.

I think if you can sort him out, and can enforce rules about when TV and wii happen, and food too, you will find it much easier to deal with the sleep time stuff. Good luck