Who is Dr. William Hutchings Jr. from The River Between Us and what is their importance?

Dr. William Hutchings Jr. is Howard's father, and for all intents and purposes the son of Dr. Hutchings and Tilly. He is, however, eventually revealed to be the biological child of the couple he believed to be his uncle and aunt, Noah and Delphine, the latter unable to "trust the world" to not see her for what she was and turn on her son. Nevertheless, William Hutchings Jr. has pride in all of his family, pride he passes on to his son.