PLUS Loan Disability Forgiveness Act This bill amends the Higher Education Act of 1965 to require the Department of Education to forgive federal student loans under the Federal Family Education Loan Program for a parent of a student who: (1) becomes permanently and totally disabled, or (2) is unable to engage in substantial gainful activity by reason of a medically determinable physical or mental impairment that can be expected to result in death or that has lasted (or is expected to last) for a continuous period of no less than 60 months.