It will only affect your father if there is evidence that he is assisting or involved in the your aunt's and cousin's fraud: he is not responsible for them solely because he is related.You cannot be held criminally or civily liable for your aunt's or cousin's actions, but employment in this nation is "employment at will": employers may freely decide who to hire or not hire. Certain employers, including many government agencies, would likely choose to not hire you if you have close relatives defrauding the government, if you are aware of the fraud and do not report it.