Unfortunately, I saw this happen many times when I worked at an urban school. I don’t understand how a paid preparer can steer people wrong about filing status, but I know for a fact that more than a few do it. (Typically, they have both spouses file as HofH.)
OP, I used to work in financial aid. Your father will have to file an amended return in order for you to receive federal aid. It is one of the things financial aid officers have to do … they basically have to do the job of the IRS & tell people that they filed incorrectly. Once they are aware of incorrect filing status, they are not allowed to give a student federal aid unless they obtain proof that an amended return has been filed.
I second the suggestion of asking VITA for assistance.