Globally speaking, Jonas father is important in that he shows by his role that people and situations aren't always what they seem to be. In Jonas' family unit, his mother is the brainy parent (a lawyer) and his father, a caregiver (a "Nurturer") for babies before they are placed in families. At first Jonas' father comes over as the naturally paternal and understanding parent any kid would covet. However, later in the story, the readers (and Jonas) learn that in spite of his role as a Nurturer, he sometimes kills babies simply because they don't fit into society's plan and are declared better off "Elsewhere." His nonchalent dismissal upon killing a twin - "Bye, bye, little guy - shows complete moral and emotional detachment, as he shoves the body of the newborn down a garbage chute after giving him a lethal injection.
In the story line of The Giver, Jonas gets attached to Gabriel, a baby his family has taken home until he is permanent placed, and is horrified to discover that Gabriel, a fretful baby who has trouble sleeping through the night, will be "released," too. Jonas makes the critical decision to escape with "Gabe" before he is terminated, even if it means leaving his family, the Community and everything he has ever known behind.