The youngest (Ethan) graduated from high school in 1997 and from the University of Illinois at Champaign/Urbana in either 2001 or 2002. He works in D.C., possibly at a lobbyist. The older son lives and works in the Chicago area and I believe he is married and may have children. Jean, Hastert's wife, retired from Yorkville Grade School about four years ago. Both she and Dennis taught in the Yorkville school district for the majority of their teaching careers. In fact, Hastert continues to be "on leave" from his former position as wrestling coach and history teacher at the high school and was ranked #1 in years of experience at the district. For many years, they owned a home between Yorkville and Oswego on the banks of the Fox River. They sold that home and moved into a newly built home outside of Plano, near Yorkville in 2002. Hastert and his wife were active members of the community and were liked and respected as well. This link to the Beacon News may be helpful because it routinely carries news about Hastert's visits to Kendall County and his activities in the surrounding area:
http://www.suburbanchicagonews.com/beaconnews/ . The local paper, Kendall County Record, is not online yet.
Note: The above is from memory - we lived in the area for eleven years and recently moved.