I can’t imagine why or how any qualified tax preparer would let a married person who lives with his wife file as Head of Household. There are very specific criteria for this status, and it’s not for married couples living in the same residence.
Your tax filing status will be flagged by the college…if your FAFSA was filed with your parents marital status as married. You will be asked to tell why that status was used (very specific reasons). If the tax filing status is incorrect, so are other numbers on your financial aid form. The 2018 tax return will need to be amended.
Take the advice above to find help for them to get this done properly.