Lil Choc, you CAN miss your dad's birthday. It IS an option. What if you were the dad and one of your married children needed to miss your birthday because he was needed at home? Surely your dad will understand? I am a dad to kids 35 & 37. If one of them were you Choc, I would want my son/daughter to stay home and take care of what is more important, the cohesiveness of a family with 4 kids. My 4 grandkids.
You see, it isn’t me that would be important; it is you and my (imaginary) grandkids that would be my priorities. I hope your dad isn’t that self centered he has to see you on one exact day.
Geez a couple of weeks, a month later, wouldn't lesson the value of my 80th birthday.