It's not clear who "he" is.
What do you mean when you say he "turned on" head of household. Do you mean that he filed his tax return as head of household?
If you and "he" live in the same household, you cannot both file as head of household. Only the one who paid more than half the cost of keeping up the home can file as head of household. If you are not married, the other person has to file as single.
