Father = God
Father in general is an affectionate term for God the Creator; if you are asking which historical figure it may relate to, his step-father Herod of Chalcis had likely passed by this stage in Jesus' life, but his brother-in-law Vespasian (married to Jesus Aristobulus sister Polla) is a more suitable paternal presence, as he was regarded by many as a father figure, being Emperor at the time.
Peace 2 All,
© Charles N. Pope, US Library of Congress. All rights reserved.