Why does Ward cut all ties to Casement in the novel, Valiant Gentlemen?

Ward’s friendship with Casement lasts until the war begins and Ward and Casement find themselves on opposite sides. Prior to the war, Ward is uncomfortable with Casement’s activism, but continues to give him money knowing that it may be used to support Casement’s cause. However, during the war, Ward cuts ties with Casement. When Ward’s son Charlie dies, Ward feels as though Casement is directly responsible.