My kids had friends with parents that were "less than ideal" to put it nicely. (One had a mother that would tell him to "Go to the store and get me a pack of ciggarettes...DON'T get caught!!" )
I treated these kids like they were my own. They rolled their eyes at something I said, they got in trouble. I gave them a time to "be home" just like my own kids, and when they were late, they got grounded like my own kids. They ate dinner with us? They helped clean up. They mouthed off? They got to spend an hour weeding the garden. They always did what I told them, they knew the alternative was to not be able to come over again...