Very simply, your husband needs to be a good roll model for the kids. There are lots of things I don't like, but when eating with my daughter I eat everything and expect her to do the same. It is very hard to get kids to eat properly and if they see one parent not eating properly then it makes it even more difficult. Flat out tell him, that even if he doesn't care about his health and dying at age 50 because of the crap he eats that's fine with you, but he must be a role model for the kids so that they don't end up like him.