I have a question that I am a foreign student in the US under F1 visa, my father arrived in Dec.8, 2014 under a B2 visa to attend my graduation ceremony and we plan to do some sightseeing after worth. He booked his round-way tickets from Dec.8, 2014 to Jan.8, 2015. However, he told the immigration officer at LAX that he will stay for one month, so he received a stamp of staying period until Jan.7, 2015.
His actual flight will be 12:40 AM on Jan.8, 2015 which he needs check in on 7th's night. Will he or I be penalized if his situation is considered as overstaying for one day? We know it is a mistake that he should say his stay is until Jan.8, but a reschedule ticket will cost almost 500 dollars, so we just wonder if he can just check in and receive a departure stamp as Jan.7 and leave as planned.