Who is Jeff from The Acid House and what is their importance?

Jeff is Brian's father. He is described as an upstanding, although rough-hewn fellow, who raised his two sons after their mother abandoned the family. Later, however, we learn that he lied about his wife never making contact or asking to see her boys. In fact, she had written repeatedly, pleading to see her sons, and Jeff had never told them. This revelation at the end of the novella is the last in a series of betrayals Brian has endured throughout the book.