From what we learn in the course of the play, Edmund (and Jamie's) grandfathers do not appear to have had much positive influence in the family. Tyrone's father, we are told, deserted his family after they emigrated to America ,leaving them to fend for themselves in a new, strange land. He returned to Ireland and there remains the suspicion that he committed suicide. Edmund, similarly once tried to commit suicide. As for Mary's dad, he died of consumption - the same illness which afflicts Edmund. He also apparently hastened his death by drinking. Edmund, too, drinks. The fate of his grandfathers certainly does not bode well for him; he seems to have inherited some of their their most negative characteristics and is probably headed for a similar end.