First, their barn is burnt down by locals who are angry with the family because Bill has gone to fight for the South.
The other is that Tom dies in battle.
Jeth starts to question the nature of the war itself, loses faith in the Generals, and also has to do more work around the farm.
During Chapter 6 and 7, the first misfortune that the Creightons have during the spring of 1862 was that their barn was set alight on fire and was burning down by the locals who were angry that Tom had betrayed his country and helped the South during the war. The next misfortune was that Tom was shot and killed instantly during war when he and Danny were watching boats with reinforcements.
This two tragedies have a sudden impact on Jethro as he witnessed the first-hand experience of the horrors of war. It gives him time to ponder whether war is necessary, loses faith in the Union army and now he has to do a one-man show, supporting the family singlehandedly,