You can't file as HOH unless you claim your grandchild as a dependent. If you have no dependents, you can't file as HOH. Furthermore, you should not even enter the grandchild's name as someone you support unless you and your daughter agree that you will claim the grandchild. Some of the questions about custody and support (which are intended for parents who are divorced or separated and live apart) will give false results when you try to use them for a child that lives with other relatives. The special rules that allow certain dependent benefits to be "split" between two people only apply to parents who live apart and share custody. A dependent can never be split or shared between a parent and other relatives.
