Can I fix papers for my dad he had a work permit back in the day and he took the citizenship test twice but he did not pass it. Can he apply again?

If you apply for your father and he files for an I-485 adjustment of status application, you and he will have to try as best you can to convince USCIS that he entered the US legally. For adjustment of status purposes, an applicant must show that he or she has been inspected and admitted or paroled into the US or that he or she qualifies through §245(i) under which he or she must have been the beneficiary of a labor certification application or immigrant visa petition by April 30, 2001 and have been physically in the US on 12/21/20 (latest iteration of §245(i). Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.