She can claim siblings as dependents if they are younger than she is, they all lived together for at least half the year, and you don't file a tax return.
She could only also claim head of household filing status if she paid more than half the total cost of maintaining the home where you all live. This includes rent or mortgage, utilities, insurance, food, and so on. I find it hard to believe a 16 year old earns so much that she paid more than half. If you got support from the state in the form of food stamps, welfare, section 8 housing; or you received child support, help from friends, a church, a shelter, a food bank, etc.; or you paid expenses from savings; that all counts as support provided by other people. Your daughter would have to pay more than the value of all other assistance combined.
It seems unlikely, and it may trigger an audit. Make sure you can prove she paid more than half the total expense, if she files as HOH.
