I don’t think it will impact the FAFSA because the principal place of residence is excluded from assets. For the CSS, assuming that your parent is only entitled to 1/2 of the equity in the home (depending on how the home is owned–joint tenancy, tenancy in common etc which you will need to check)) . they are also only able to claim half of the mortgage payment. Hopefully, someone with greater knowledge will be able to help you out on here. The CSS Profile provides very little in the way of support for questions. One thing you could do is call a financial aid office at one of the schools you are interested in and ask how they expect to be reported.