Answer:
He worries over Romeo's relationship with Rosaline (with whom Romeo was in love at the beginning of the story), but cannot get through to his son. He later pleads with the Prince to prevent his son from being executed, and gets his wish when the Prince lowers Romeo's punishment to banishment.
Romeo has been acting depressed. He has been seen going into the woods at night with tears on his face, and in the morning he comes back to the house and locks himself into the room.
