So what happened to the father?
He was obviously glad about his son growing up and getting the girl -- at least till he thought about what that meant for his prospects.
I remember in a scene prior to the birthday party, the son waits for Jack Nicholson outside the apartment, the door opens with a big group of lawyers exiting and Jack says to one of them:
"Get me that list of non-extradition countries."
Always with a plan, Jack. :)