Um why shouldn't her parents be civil and nice with him, if it wasn't for him they wouldn't get to see their small grandchildren. He didn't have to let britney's parents see the kids, he did it because he felt like doing it. When there's children involved you gotta be a grown-up, especially when britney is not exactly stable the last year, so it's important for the kids to have at lreast a father and grandparents that can not only help britney or at least try too, but look out for the kids too.